Versus Chess is a lightweight version of Yahoo Chess for the iPhone. The implementation of the game is basic -- there are no timers, no types of games, no rooms -- but Versus Chess is one of the first of its kind, offering true one-on-one gameplay on the iPhone over the internet.
At the time of this review there was only one other human on line, and two bots (one with ranking 850, the other ranking 1400). So if you just want to play a good game of chess versus the computer, there are other Chess apps for iPhone. Also, at $8.99 the app is overpriced. Still, if you are seriously into the game, you might want to take a flier.