which micro controller you using to interface RFID… let us know where excatly you got struct……..
here are some links which might help you out going through RFID
What is rfid? how it works? basics of RFID…
http://www.engineersgarage.com/rfid-radio-frequency-identification-and-detection
how to interface RFID with 8051??
http://www.engineersgarage.com/microcontroller/8051projects/interface-rfid-AT89C51
interacing of RFID with 8051 using interrupt concepts
http://www.engineersgarage.com/microcontroller/8051projects/interface-rfid-AT89C51-serial-interrupt
A small project with RFID security system…
http://www.engineersgarage.com/microcontroller/8051projects/rfid-secured-access-system-at89c51
toll plaza system using RFID
http://www.engineersgarage.com/microcontroller/8051projects/simple-toll-plaza-rfid-interface-at89c51