i've just played a couple of games on FIBS from my iphone using Backgammon Online ($4.99 from itunes app store) and participated in public chat
the software worked very well; much better than i had anticipated, just setup your login and 'set ready', then u can invite players (or accept invite)- i chose folks i knew, but they shunned me
so i chose from a list of iphone users.
the games were brisk and the second one finished even tho' he was beaten and had a bad rep.
for the record i was using a connection on wifi, with the phone carrier disconnected, and was up and running in minutes playing my first game...great
the first game i just accepted the dice - i hadn't read how shaking the phone 'undoes the move' or clicking the dice to swop the first played.
very impressed - i recommend it to to u iphoners! (private chat is available too as is help) http://multimedia-go.de/bgonline