I happen to be using comcast as my cable provider (the suck, I know). I have been reading over the net that with mythtv there is a way to control the cable box channel changing via firewire. My question is are there any recommended firewire cards that I should use seeing that the PC im useing does not have firewire. In order to make everything below here is the equipment that I will be useing on my mythtv. Could anyone point me in a correct direction regarding the firewire or let me know that I am hosed because im using comcast.

westerndigital 750gb hdd
StreamZap remote

Cable box
DCT6200 (with firewire)