XPTracker now makes it's official home on sourceforge.net! Right now, the tracker is available through the svn hosting provided by sourceforge. Just use this command to get a copy into a folder called XPTracker:
svn export https://xptracker.svn.sourceforge.net/svnroot/xptracker/trunk XPTracker
Alternatively, you could use the checkout command if you're interested in developing, (instead of export)