but wait, can you stream other music or is it just your own library?
Music Beta by Google Play
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I spent months painstakingly transferring my entire CD collection onto my ipod. Then disaster struck, my hosting PC died and I discovered that itunes makes it very hard to transfer non-itunes purchased songs. Now I have them in the cloud and I can access them from anywhere using Google Music.
Smooth experience and nice interface. Uploading not the swiftest (and it decided not to upload a large number of files without explanation -- possibly based on metadata? or something else?), but once the files are in, great performance. Instant mix function works well (and throws up some welcome surprises).