Well, for Urban Terror, all you really need is your tag. Perhaps you can leave an open area for which servers you use most often, too. The best I can do for a little logo is this http://en.wikipedia.org/wiki/Urban_Terror. The logo on that page would probably do nicely.
For GGPO all you need is a username as well. That logo is here (Upper left corner of the screen.)
Unfortunately, I think I'm going to have to give up GGPO for a while because it's quite addicting and I've found myself playing for hours on end compulsively.
Urban Terror I will still use occasionally, though. And I'd love to get together with some people and play that every now and then.