A search didn't turn up this app, so I thought I'd share...
HomePipe has a free version in the marketplace, let's your stream iTunes, MP3s and other files to your phone.
I saw it on
Engadget before launch. Just got around to installing.
I have a crap-ton of tracks at home so this is nice when I don't feel like using Pandora...
You can also access your "mystuff" page from any other computer by signing into your account. I think there are a few others out there, but this has worked well for me so far...