I haven't seen many games using UE3 support AA of any form at this stage, and it's due to how the buffers are calculated. However, I'll experiment and see if I can get an edge detection + blur working as a post process effect. No idea on time frames though ... so don't expect this anytime soon!
I often have issues with Steam-games that use the UT3 engine - Borderlands, Bioshock, and now The Ball as well.
Couldn't get FSAA to work, no matter what I tried in my nVidia-CP.
For Bioshock, I set my desktop-settings to the ones I wanted ingame (was the only way for me). Downside was, that I had to do it everytime I wanted to play the game, and then reverse back to original desktop-settings, once I had finished playing.
For Borderlands, however, I used the suggestion in this post: