Variable Infra-red Transmitter?

[nirvanas silence]

I have been playing laser tag and I've found out that my Charter digital cable box remote set to VCR setting for a RCA VCR sets off the laser.  Does anyone know a simple circuit that I can sweep the frequency (is that the variable) of the infra red transmitter.  Also, I'm new to this, so do i need a specific infra-red LED or do all infra-red LEDs work the same?