Mpc.el is an Emacs front end to the Music Player Daemon.
It mostly provides a browser inspired from Rhythmbox for your music collection and also allows you to play the music you select. The basic interface is somewhat unusual for mpd in that it does not provide direct access to MusicPD's playlist functionality. Instead it uses MusicPD's playlist internally to implement a queue of songs. This means that it does not always interact nicely with other clients that you may be using at the same time.
I play albums rather than songs and thus don't have much need for playlists, and it shows. Playlist support exists, but is embryonic. The intention is to handle playlists just like any other attributes. I.e. placing a file in playlist FooSongs is treated as equivalent to adding a tag "playlist=FooSongs".
The package is in the early stage of development. If you're not interested in fiddling with the code, it's probably too early for you to try it out. But if you do try it out, please tell me how it goes.
It is developed with Emacs-CVS and should work with Emacs-21 as well (i.e. it's been lightly tested under and adapted to Emacs-21).