A new convertion for UT2004 is out: UTXMP (www.utxmp.com).

They have only relesed the windows package at this time but hte linux zip should follow shortly.

UTXMP is a remake of the XMP (extended multiplayed pack) addon for Unreal II, which is a class based mutiplayer combat FPS, similar to the Tribes series in some ways (multiple classes, deployables, ...)

It looks like they kept all the "good" of XMP, but upgraded the "bad" using the better Unreal engine from UT2004.

XMP requires a lot of team coordination and has a bit of a learning curve (like Tribes) but is a lot of fun to play. I'll post back when the linux version is available.

If you have a windows machine and the UT2004 know-how, you can probably grab the right stuff from the windows install and transplant it onto your linux machine.