A simple RFID reader based on the Grand Idea Studio Reader from Parallax and an Arduino Duemilanove. After pressing the push button on the breadboard the sketch waits for an RFID and then outputs it on a Serial LCD.
Plug the reader into the 4 pin female header with the silkscreen facing down. The display goes in the 5 pin header (it works both ways but only fits one way on my setup). Compile and upload the Arduino sketch to the board. Reboot the Arduino, hold an RFID to the reader, press the button and the tags id is output on the display.