But please be aware of the fact that it's currently on alpha stage thus you might encounter bugs which happened to me as well. For instance when you run it for the first time it asks for your music collection folder. But while I was using it for some reason it could not "remember" my music folder thus I always had to manually put the folder location every time I launched it! which is obviously frustrating.
But as said before this is still in its very early stages thus things like these should be expected but just because I had this issue doesn't mean that you'll encounter by it either.
Update (4/12/2012): As you can see from the below comment (by the developer), the development of "pymusic" is officially stopped. But that doesn't mean that you cannot use it if it works on your distribution though :).
*. It uses the Gstreamer multimedia framework and can handle MP3 and OGG files only it seems at the moment.
*. Very simple GUI and no menus either!.
*. Add multiple folders.
*. Arrange your songs via "Artist Name" or "Song names".
*. A big "missing" feature is the "progress bar" which lets you go to a preferred location in a file manually. So basically you just can't jump into the time-frame that you want which is a MUST!. As said this is still in alpha stage but this must have been there (or may be it's another bug :/...).
That's about it for features. There are no ".deb" packages at the moment but you can install PyMusic in Ubuntu 11.04 Natty Narwhal (might work on the 10.10 and 10.04... not sure though) by simply downloading the archive from here.
Then extract the content and open your Terminal and change directory to that extracted folder and enter the below command.
sudo make install
To launch it in Unity just search for "pymusic" or press "Alt" + "F2" keys on your keyboard and use the same command in the box.
The current version in 0.2.5 but you can check out whether the maintainer/developers has new updates, etc from his launchpad page in the future.
As said I won't be using it because of the issues and the "missing progress bar" (hope it's not a simplistic features like with Gnome :/) I had but one thing for sure I'll keep a close eye on this little app because after considering its speed ... when a stable release it available I'll most definitely be trying it again!.