MPaD is your iPad remote control for MPD (Music Player Daemon), and as such is the bigger brother of MPoD. Featuring a slick, intuitive user interface, MPaD makes it very easy to browse through your collection, and play the music you want to hear from a large collections of artists, albums and songs.
Note that MPaD is not a stand-alone application: it will only work in combination with MPD, and it doesnt play music on your iPhone. If you dont have an MPD server running in your home (which usually runs on Linux) then MPaD will not provide any value to you.
You can find details on MPD at http://www.musicpd.org.