Since I'm running MPD on the NSLU2, it can be a pain to open a terminal, fire up ncmpc, and adjust the volume or tell MPD to connect to something other than the SlimServer. Because of this, I adapted Thomas Morgan's PHP-based Client:Mpd.
It works okay without modification (be sure to edit the "host" entry in both index.php and playlist.php) but I found the text-only interface to be a bit too spread out. So, I replaced the text in his links with graphics, reordered them, changed the link colors, and added a meta refresh to index.php.
The end result is a bit cheesy (I need to find a decent set of graphics to "skin" this with) but it's functional: