If you want an affordable wireless speaker solution for your home and like me you have a lot of restricted audio formats that won’t play in iTunes (or if iTunes just bugs the nipples off you) there is great news!
Remote Speakers Output Plug-In will send streams to your Airport Express speakers through Winamp! No iTunes installation required. It will even allow you to control the volume through Winamp and works with the remote control.

I just purchased it today for next to nothing through PayPal and it works beautifully! Eric, the creator, was very helpful and responded quickly when I had problems getting it to work at first. You can test it out for 2 weeks for free too.
Here’s the Winamp Plugin page with reviews.