for what it would cost to get a wireless TX and a RX unit with built in amp, you could run new wiring and mount them yourself. my unit has speaker A&B connections, i ran a second set of wires to my back porch so i can put my speakers out there when we have a cook out or outdoor party. when not in use, i turn off speaker B output.

are you thinking about something like Sonos?

Thanks, I looked into Sonos, that's much more involved than what I'd like.

I guess for the purpose of playing music in a different room, I could just buy an additional basic receiver with new loudspeakers and plug an airport into it and control the music from my computer.

But I was also hoping to free the connection between speakers and my dvd player to be able to project the video onto the opposite wall. Wires are hard to run discretely in my house.

update: after much research and almost giving up, I finally found what I was looking for and more. Check out Audioengine. http://audioengineusa.com/

They have a simple hookup sender and receiver that can go between:
computer and powered speakers,
computer and receiver
ipod (or other device) and pwered speakers
surround receiver and powered speakers as rear channel speaker
receiver to subwoofer.

I also bought their powered speakers after reading raving reviews, and wow am I impressed!!!!

Here is a link that might be useful: http://audioengineusa.com/