On Microsoft's website, they claim that there are some HTPC's using XP Media Edition that can control the standard satellite boxes (changing channels) via a serial connection. Has anyone found one of these?
Some tv tuner cards like the Hauppauge 150, 250, 350 etc come with an IR Blaster. This plugs into the tuner card and the other end is a little ir emitter that sticks to the front of your cable or satellite box. It then resends the commands to your box, when you use the tuner remote or your keyboard and mouse.