The ATTiny85 based mini development board is similar to the Arduino, but cheaper and smaller (of course a bit less powerful). With a whole host of shields to extend its functionality and the ability to use the familiar Arduino IDE, this board is a great way to jump into microcontroller electronics.
APPLICATIONS: Support for the Arduino IDE 1.0+ (OSX/Win/Linux). Power via USB or External Source – 5v or 7-16v (automatic selection). On-board 150ma 5V Regulator.
Built-in USB (and serial debugging). 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 boot loader) I2C and SPI (via USI) PWM on 3 pins (more possible with Software PWM) ADC on 4 pins Power LED and Test/Status LED.