hello sciencetronot…
i here i am sending you some of links related to RFID…
What is RFID how does it works??
http://www.engineersgarage.com/rfid-radio-frequency-identification-and-detection
RFID interfacing using AVR..
http://www.engineersgarage.com/embedded/avr-microcontroller-projects/rfid-interfacing-circuit
RFID interfacing using AVR interrupt concepts…
the above two links for AVR interfacing with RFID is using ATmega16 but the same concept is applied on ATmega8… go throught these links… an if face any problem in future let us know we will try to solve that out….