[Eric T]

I would strongly recommend buying an sstran kit or an updated version of a phonograph oscillator like the one AES sells. By the time you have finished drilling holes, installing switches, figuring out where to break the circuit, trying to get the impedances matched on one radio you can be on the air with a part 15 transmitter broadcasting to every radio in the house.
Regards
Arran

I'll second what Arran said.

I'm not sure if linking to the barking dog forum is OK, but there is a thread there for a LM386N transmitter that can be built in a few hours for about $15 with parts from Mouser.com. It sounds unbelievably good for something so cheap and easy to make.