A tutorial over at hackaddict will give you the 1-2-3 on how to stream your iTunes to your Wii. You'll need a Wii (le duh) complete with Opera browser installed, iTunes, and MyTunesRss, which is a free download that works on Mac, Linux, and Windows.
The bad news is that many songs purchased on iTunes--those that aren't DRM-free--won't work using this system. There are a few other potential hiccups as well, so be prepared for some tinkering if you give this a shot.
Tutorial: iTunes on the Wii (for free!!) [hackaddict]
