For those who want to try it out.  I've defaulted my chicago server ( cq.game.nfoservers.com ) to 10 player FFA DM with WREX enabled.  If you want to find it in server browser its called: - [cQ] Chicago WREX Anti Cheat Required Server -

To get the wrex client download it here:
http://getwrex.mangemesboules.fr/

Unless you are cheating the only way to test it is join the server without wrex running and watch it kick you.  Exciting I know.  Then quit UT3, load up wrex, do a scan, load UT3 and join my server again.  Odds are you'll be playing with bots since this is new, but if there are people in there you will know they are legit.