If link above is not complete/functional, point your browser here:
http://www.howtogeek.com/howto/*****/wirelessly-sync-share-your-music-collection-with-any-mobile-phone/_I've tried this and it works beautifully with my Droid X. Works with Android & iPhone.

"Have an iPhone or Android phone and a music collection too large to sync to it? Want to share your library with friends? Here's how to sync your library with your smart-phone over the internet, or stream it in any browser.

Subsonic is a powerful little cross-platform solution to these problems and moreit's an open source media streamer that is based on both Java and donations, so it's a cross-platform solution that is free for basic usage utilizing the web interface.

Note: In this guide we're going to be showcasing two mobile clients which use the Subsonic API which is NOT free. You'll get a 30-day window to try out the setup, after which you'll be required to make a minimum 10 donation, which will give you access to all the clients including an Adobe AIR client, and a few bonuses, like removing the ad from the web interface, free future upgrades, and a yourname.subsonic.org server address. If you choose to not donate, you can continue using the web client at no extra cost. You can more details at the Subsonic Apps page.

Head over to their download page and grab the installer for free. Double-click the file and Subsonic will be installed as a service which will automatically start with Windows. Note: While installing Subsonic on Mac OS X and Linux is also relatively quick and easy, to get support for transcoding requires a little more effort. Be sure to check the Installation Instructions.

Once you've installed Subsonic, open up a browser and point it to http :// localhost/. Under the login, you'll notice a warning message that gives you the default username and password and reminds you to change it as soon as you login".

Great music sharing mechanism.
Best,
Ron