You need pygtk
You need ubuntu jaunty or debian unstable (glade 3.6 and libgtk 2.16)
You need python-gtk-vnc

Install rrdtool for graphs

To launch openxenmanager:

python window.py

Please visit #openxenmanager in irc.freenode.net to talk about alpha version
Or send me mail to alberto@pesadilla.org with "openxenmanager: " subject