music playback is realized through music player daemon, so mpd and mpc should be installed and configured.

python libraries needed:

eyed3
cheetah
webpy
-> all available via ubuntu apt

pylast -> download from http://pypi.python.org/pypi/pylast
Execute "python setup.py install" as a super user to install pylast

initial setup:
Install music player daemon
MPD Guide: http://mpd.wikia.com/wiki/Configuration

You will also need the programm "MPC" to communicate with the Music Player Daemon via shell
install it also via ubuntu packet manager

open settings.py and change variable "musicfolder" to "/path/to/your/musicfolder"
the path should be the same path you used in the in your mpd config file

run: python createMusicLib.py in a terminal
to create the music database
check if mucke.db file was created

start WebDJ with:
run: python webpy.py
access webinterface via http://localhost:8080/ with your browser of choice
vote songs and have fun!