How about an iphone roster app?
Asked for it last year, HT was "rolling on the floor laughing" when it was suggested it would be a simple thing to create. Apparently creating such a thing is more difficult/time consuming than meets the eye. Not to mention likely far, far down the current priority list.
I do like the idea though still, being able to check out who is online, how many online, even general chatter/goings on in the arenas when you aren't actually at your gaming system.