Guide to ripping and encodeing under linux:
http://www.bunkus.org/dvdripping4linux/en/single/index.html

Monitor These lists for changes to the CVS sources of XVID
http://edu.bnhof.de/pipermail/xvid-devel/

Unoffical Debian APT sources I use (with apt-pinning testing/unstable)

# Video Packages like transcode, mplayer, xvid
deb http://marillat.free.fr/ testing main

# Video Packages like transcode, mplayer, xvid
deb http://marillat.free.fr/ unstable main

##RAREWARES AAC/MP4 (faad2, faac, aac/mp4 playback plugins)
deb http://pessoal.onda.com.br/rjamorim/debian/ ./

##RAREWARES MAIN (lame, lame-ha, lamip, cue2toc, shntool)
deb http://rarewares.hydrogenaudio.org/xmixahlx/debian/ ./
deb http://xmixahlx.dyndns.org/debian/ ./

# mkvtoolnix
deb http://www.bunkus.org/debian/unstable/ ./

those are some media sources to add to your sources.list for debian sid. I don't know how that works w\ unbuntu but last i checked unbuntu already had the packages they just needed to be installed. xmms should then work with it.
question i am on debian sid, what are the sources you used to get howl and mt-daapd. are they part of the standard or did you find them somewhere else? thanks