Maestro : On-Demand access to your music at home from anywhere.
"Maestro lets you stream music from your computer across the web, for easy listening anywhere. This is a lot like what music locker services Oboe, MediaMaster, and Orb are doing with a social networking twist. Not only can you stream music from your own computer using Maestro, but you can also stream music from your friends on the network (Oboe lets you share channels with friends, but through email links). They plan on expanding to other types of media in the future.", from TechCrunch.
Maestro's working on an invite-only basis at this time, so... tough.
NuTsie : Listen to your iTunes on your mobile phone.
"Here's a way to listen to your iTunes library on cellphones other than the iPhone: NuTsie, a beta application that just launched today, holds a huge library of music, and any songs you have in your iTunes library can be listened to on your cellphone. Notice that name, NuTsie? Cute. It's an anagram of iTunes.", from Gizmodo.
I'm really excited about NuTsie, because it works around the whole iTunes DRM issue. What NuTsie has you do is simply upload your playlist, not your songs. So, I uploaded my library to NuTsie, and I tried installing NuTsie on my Samsung Blackjack, and I got this error message : "Installation failed, errno=910 Application authorization failure". Bah! I'd love to hear your experience if you got it to work.