Teensy USB AVR with Teensyduino - PJRC

The Teensy is available with header pins, for direct no-soldering-required use on a breadboard, which can also be run from the +5 volt from the USB cable. Standard Teensy boards come with solder pads. Either way, all Teensy boards come fully assembled and tested, so no surface mount soldering is needed.
Some Features
- USB can be any type of device
- AVR processor, 16 MHz
- Single pushbutton programming
- Easy to use Teensy Loader application
- Free software development tools
- Available with pins for solderless breadboard
From - PJRC Electronic Projects