Here is a very simple breadboard power supply kit that takes power from a DC wall wart and outputs a selectable 5V or 3.3V regulated voltage. The .1" headers are mounted on the bottom of the PCB for simple insertion into a breadboard. Pins labeled VCC and GND plug directly into the power lines. The lone pair of pins have no electrical connection but help support the PCB. Project description, more information and ordering can be found at https://www.sparkfun.com/products/114 Quickstart Guide: http://www.sparkfun.com/tutorials/297