Support for the Arduino IDE 1.0+ (OSX/Win/Linux)

Power via USB or External Source – 5v or 7-35v (12v or less recommended, automatic selection)

On-board 500ma 5V Regulator

Built-in USB

6 I/O Pins (2 are used for USB only if your program actively communicates over USB, otherwise you can use all 6 even if you are programming via USB)

8k Flash Memory (about 6k after bootloader)

I2C and SPI (vis USI)

PWM on 3 pins (more possible with Software PWM)

ADC on 4 pins

Power LED and Test/Status LED