I have a Radio Shack "Wireless Audio Link" that I use for the rear speakers in my surround setup. A little transmitter takes speaker wire input off my tuner, transmits to a receiver with an amp in it, which sits behind the couch, and routes sound to the rear speakers on tables on either side of the couch.
I can't find it on their website anymore, but if you go into the store and ask, you might get lucky. I did find this on their website:
http://www.radioshack.com/product.as...t%5Fid=15-2572
Only thing is, that doesn't do speaker wire input and output, only RCA. But it also transmits video, which I believe I could probably find some uses for!