"Taking easy-to-use, mass-market microcontroller technology to
the next level is the Arduino.
"This little package measures 2.75 x 2.50 inches, has a USB
interface, 14 digital I/O pins, 6 analog pins, a socketed ATMega168
chip, and a recommended supply voltage of 7 to 12 volts. Did I
mention that the board can run standalone from a 9 volt battery or
right off of the USB connection. The thing retails for $34.95 from
Sparkfun. There's also an Arduino Stamp, which is actually about
the size of two US stamps, that sells for $37.95. Either way,
they're considerably cheaper than the Basic Stamps.
"Ready for the best part? You can program them from your
favorite version of Linux!"