Well, for the AM/FM receiver part, take a close look at this long thread:
HU Quality AM/FM RDS/RBDS Radio with Features
It's interesting, and they're getting to the point of prototype hardware.
As for the TV, you'd need a PCI or USB TV Tuner card.
Ones with hardware MPEG2 or MPEG4 on board are generally better, but a software-based card will do sometimes.
I have an ATI TV Wonder PCI TV tuner card for my desktop, and the card itself is OK, but the software and drivers kind of blow.