since you are looking for mods, and yer a n00b (newbie) I'll give ya a bit of advice. You should really copy your entire UT\System folder and store it somewhere safe. Cause some of those mods that have been suggested (they all kick A$$) will do some weird things to your UT. Then when you tire of the mods or just wanna uninstall it (or if you are having UT prob's) you can just copy/paste it from your backup, and it's back to normal.
I agree, Rocket Arena kicks it up a notch if you like 1v1. U4e is a great mod too, lotsa cool weapons and stuff. There's also Darkmatch, StrikeForce, Infiltration and Dominator. Only 100's of them to choose from, check out Fileplanet's list of mods or you can visit some of the hosted PU sites like modsquad.
Places you can get really good maps is the CliffyB ownage page, NaliCity, Unreality (all maps are rated by users), Mapped, etc. Check out all the links for 'Levels' on PU's front page.....Soooo many good maps, it's hard to keep track of em all.
