Ubuntu One Music app for Android streams your tunes
Now in beta testing, the Music App allows you to (brace yourself!) stream music which you've previously stashed in your Ubuntu One storage. Right now, there are some rather glaring omissions: there's no playlist or album art support, and only MP3 files are supported -- you can't play OGG, which is a little odd considering Ubuntu doesn't include an MP3 decoder out-of-the-box (though Maverick has added an option during the installation process).
Interestingly enough, Ubuntu One users already sort of had this functionality. 7digital -- who provide the plumbing for the Ubuntu One Music Store -- already offer streaming apps for Android and Blackberry users, though they're only connected to your 7digital locker.