I've used the X-10 example in the PicBasic Pro manual along with a TW-253 interface to control lights, and turn the Christmas tree on and off. The modules are inexpensive, I got mine from Radio Shack. For driving relays I usually use the ULN2803, a darlington driver chip that will drive up to eight relays, (but not all eight at once,) I also like the Omron relays.

Jerry.