You can have your whole music library streamed as an online radio station for free.
Go to
www.mediamaster.com and upload your music ( don't forget to add it to your radio staion) They will give you the URL for the streaming radio station.
Then load GSPlayer on your mobile device
http://www.freewareppc.com/multimedia/gsplayer.shtml
And open your radio URL from within GSPlayer. I listened to it for an hour straight on my ride into work this morning with no problems, before I got to my desk and turned it off.
Good luck!