[StylinProfilin]

Like an mSpot? Or Isyncr? This is essential for me. Cloud(server) app.

[electricbopeep]

I think JukeFly might fit the bill:

Listen to Your Music Anytime, Anywhere JukeFly allows you to stream your personal music library from your home PC running the free JukeFly software, to your Windows Phone 7 over WiFi or 3G* Features: - Stream your music from your PC running JukeFly software - View additional enriched content around your music, including artist bios, lyrics and videos - Easy setup means no fuss or technical knowledge needed for firewall or router stuff Windows Phone 7 Exclusive features - Built for Windows Phone 7 Metro UI look and feel - Social features for the music you’re listening to (Update your FaceBook wall, Tweet or send a Musicnote to your friends and show off the latest tunes you’re listening to.) - Offline listening – Carry on rocking to your tunes even if you don’t have a data connection. Specify playlists that you want with you all the time! If you’re new to JukeFly, all you have to do is sign up for a free account, install the JukeFly Personal Server on your PC and within minutes you can be streaming your entire music library. *Data connection plan required for streaming over 3G and data use and charges may occur.

I've uploaded my collection to it but have only used it to stream a few times. Haven't really used it enough to be able to recommend it.