Demo Code from Adafruit:

/*********************************************************************
 * This is an example for our Monochrome OLEDs based on SSD1306 drivers
 * 
 * Pick one up today in the adafruit shop!
 * ------> http://www.adafruit.com/category/63_98
 * 
 * This example is for a 128x64 size display using I2C to communicate
 * 3 pins are required to interface (2 I2C and one reset)
 * 
 * Adafruit invests time and resources providing this open source code, 
 * please support Adafruit and open-source hardware by purchasing 
 * products from Adafruit!
 * 
 * Written by Limor Fried/Ladyada  for Adafruit Industries.  
 * BSD license, check license.txt for more information
 * All text above, and the splash screen must be included in any redistribution
 *********************************************************************/

#include 
#include 
#include 
#include 

#define OLED_RESET 4
Adafruit_SSD1306 display(OLED_RESET);

#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2


#define LOGO16_GLCD_HEIGHT 16 
#define LOGO16_GLCD_WIDTH  16 
static const unsigned char PROGMEM logo16_glcd_bmp[] =
{ 
        B00000000, B11000000,
        B00000001, B11000000,
        B00000001, B11000000,
        B00000011, B11100000,
        B11110011, B11100000,
        B11111110, B11111000,
        B01111110, B11111111,
        B00110011, B10011111,
        B00011111, B11111100,
        B00001101, B01110000,
        B00011011, B10100000,
        B00111111, B11100000,
        B00111111, B11110000,
        B01111100, B11110000,
        B01110000, B01110000,
        B00000000, B00110000 };

#if (SSD1306_LCDHEIGHT != 64)
#error("Height incorrect, please fix Adafruit_SSD1306.h!");
#endif

void setup()   {                
        Serial.begin(9600);

        // by default, we'll generate the high voltage from the 3.3v line internally! (neat!)
        display.begin(SSD1306_SWITCHCAPVCC, 0x3c);  // initialize with the I2C addr 0x3D (for the 128x64)
        // init done

        display.display(); // show splashscreen
        delay(2000);
        display.clearDisplay();   // clears the screen and buffer

        // draw a single pixel
        display.drawPixel(10, 10, WHITE);
        display.display();
        delay(2000);
        display.clearDisplay();

        // draw many lines
        testdrawline();
        display.display();
        delay(2000);
        display.clearDisplay();

        // draw rectangles
        testdrawrect();
        display.display();
        delay(2000);
        display.clearDisplay();

        // draw multiple rectangles
        testfillrect();
        display.display();
        delay(2000);
        display.clearDisplay();

        // draw mulitple circles
        testdrawcircle();
        display.display();
        delay(2000);
        display.clearDisplay();

        // draw a white circle, 10 pixel radius
        display.fillCircle(display.width()/2, display.height()/2, 10, WHITE);
        display.display();
        delay(2000);
        display.clearDisplay();

        testdrawroundrect();
        delay(2000);
        display.clearDisplay();

        testfillroundrect();
        delay(2000);
        display.clearDisplay();

        testdrawtriangle();
        delay(2000);
        display.clearDisplay();

        testfilltriangle();
        delay(2000);
        display.clearDisplay();

        // draw the first ~12 characters in the font
        testdrawchar();
        display.display();
        delay(2000);
        display.clearDisplay();

        // draw scrolling text
        testscrolltext();
        delay(2000);
        display.clearDisplay();

        // text display tests
        display.setTextSize(1);
        display.setTextColor(WHITE);
        display.setCursor(0,0);
        display.println("Hello, world!");
        display.setTextColor(BLACK, WHITE); // 'inverted' text
        display.println(3.141592);
        display.setTextSize(2);
        display.setTextColor(WHITE);
        display.print("0x"); 
        display.println(0xDEADBEEF, HEX);
        display.display();
        delay(2000);

        // miniature bitmap display
        display.clearDisplay();
        display.drawBitmap(30, 16,  logo16_glcd_bmp, 16, 16, 1);
        display.display();

        // invert the display
        display.invertDisplay(true);
        delay(1000); 
        display.invertDisplay(false);
        delay(1000); 

        // draw a bitmap icon and 'animate' movement
        testdrawbitmap(logo16_glcd_bmp, LOGO16_GLCD_HEIGHT, LOGO16_GLCD_WIDTH);
}


void loop() {

}


void testdrawbitmap(const uint8_t *bitmap, uint8_t w, uint8_t h) {
        uint8_t icons[NUMFLAKES][3];

        // initialize
        for (uint8_t f=0; f< NUMFLAKES; f++) {
                icons[f][XPOS] = random(display.width());
                icons[f][YPOS] = 0;
                icons[f][DELTAY] = random(5) + 1;

                Serial.print("x: ");
                Serial.print(icons[f][XPOS], DEC);
                Serial.print(" y: ");
                Serial.print(icons[f][YPOS], DEC);
                Serial.print(" dy: ");
                Serial.println(icons[f][DELTAY], DEC);
        }

        while (1) {
                // draw each icon
                for (uint8_t f=0; f< NUMFLAKES; f++) {
                        display.drawBitmap(icons[f][XPOS], icons[f][YPOS], logo16_glcd_bmp, w, h, WHITE);
                }
                display.display();
                delay(200);

                // then erase it + move it
                for (uint8_t f=0; f< NUMFLAKES; f++) {
                        display.drawBitmap(icons[f][XPOS], icons[f][YPOS],  logo16_glcd_bmp, w, h, BLACK);
                        // move it
                        icons[f][YPOS] += icons[f][DELTAY];
                        // if its gone, reinit
                        if (icons[f][YPOS] > display.height()) {
                                icons[f][XPOS] = random(display.width());
                                icons[f][YPOS] = 0;
                                icons[f][DELTAY] = random(5) + 1;
                        }
                }
        }
}


void testdrawchar(void) {
        display.setTextSize(1);
        display.setTextColor(WHITE);
        display.setCursor(0,0);

        for (uint8_t i=0; i < 168; i++) {
                if (i == '\n') continue;
                display.write(i);
                if ((i > 0) && (i % 21 == 0))
                        display.println();
        }    
        display.display();
}

void testdrawcircle(void) {
        for (int16_t i=0; i<display.height(); i+=2) {
                display.drawCircle(display.width()/2, display.height()/2, i, WHITE);
        }
        display.display();
}

void testfillrect(void) {
        uint8_t color = 1;
        for (int16_t i=0; i<display.height()/2; i+=3) {
                // alternate colors
                display.fillRect(i, i, display.width()-i*2, display.height()-i*2, color%2);
                color++;
        }
        display.display();
}

void testdrawtriangle(void) {
        for (int16_t i=0; i<min(display.width(),display.height())/2; i+=5) {
                display.drawTriangle(display.width()/2, display.height()/2-i,
                display.width()/2-i, display.height()/2+i,
                display.width()/2+i, display.height()/2+i, WHITE);
        }
        display.display();
}

void testfilltriangle(void) {
        uint8_t color = WHITE;
        for (int16_t i=min(display.width(),display.height())/2; i>0; i-=5) {
                display.fillTriangle(display.width()/2, display.height()/2-i,
                display.width()/2-i, display.height()/2+i,
                display.width()/2+i, display.height()/2+i, WHITE);
                if (color == WHITE) color = BLACK;
                else color = WHITE;
        }
        display.display();
}

void testdrawroundrect(void) {
        for (int16_t i=0; i<display.height()/2-2; i+=2) {
                display.drawRoundRect(i, i, display.width()-2*i, display.height()-2*i, display.height()/4, WHITE);
        }
        display.display();
}

void testfillroundrect(void) {
        uint8_t color = WHITE;
        for (int16_t i=0; i<display.height()/2-2; i+=2) {
                display.fillRoundRect(i, i, display.width()-2*i, display.height()-2*i, display.height()/4, color);
                if (color == WHITE) color = BLACK;
                else color = WHITE;
        }
        display.display();
}

void testdrawrect(void) {
        for (int16_t i=0; i<display.height()/2; i+=2) {
                display.drawRect(i, i, display.width()-2*i, display.height()-2*i, WHITE);
        }
        display.display();
}

void testdrawline() {  
        for (int16_t i=0; i<display.width(); i+=4) {
                display.drawLine(0, 0, i, display.height()-1, WHITE);
        }
        display.display();
        for (int16_t i=0; i<display.height(); i+=4) {
                display.drawLine(0, 0, display.width()-1, i, WHITE);
        }
        display.display();
        delay(250);

        display.clearDisplay();
        for (int16_t i=0; i<display.width(); i+=4) {
                display.drawLine(0, display.height()-1, i, 0, WHITE);
        }
        display.display();
        for (int16_t i=display.height()-1; i>=0; i-=4) {
                display.drawLine(0, display.height()-1, display.width()-1, i, WHITE);
        }
        display.display();
        delay(250);

        display.clearDisplay();
        for (int16_t i=display.width()-1; i>=0; i-=4) {
                display.drawLine(display.width()-1, display.height()-1, i, 0, WHITE);
        }
        display.display();
        for (int16_t i=display.height()-1; i>=0; i-=4) {
                display.drawLine(display.width()-1, display.height()-1, 0, i, WHITE);
        }
        display.display();
        delay(250);

        display.clearDisplay();
        for (int16_t i=0; i<display.height(); i+=4) {
                display.drawLine(display.width()-1, 0, 0, i, WHITE);
        }
        display.display();
        for (int16_t i=0; i<display.width(); i+=4) {
                display.drawLine(display.width()-1, 0, i, display.height()-1, WHITE); 
        }
        display.display();
        delay(250);
}

void testscrolltext(void) {
        display.setTextSize(2);
        display.setTextColor(WHITE);
        display.setCursor(10,0);
        display.clearDisplay();
        display.println("scroll");
        display.display();

        display.startscrollright(0x00, 0x0F);
        delay(2000);
        display.stopscroll();
        delay(1000);
        display.startscrollleft(0x00, 0x0F);
        delay(2000);
        display.stopscroll();
        delay(1000);    
        display.startscrolldiagright(0x00, 0x07);
        delay(2000);
        display.startscrolldiagleft(0x00, 0x07);
        delay(2000);
        display.stopscroll();
}