It hasn't been until recently that I've really begun to explore my iPhone's capacity for online gaming. I've come to the conclusion that it's certainly not the best platform for drawn-out battles, but it's great for quick random matches. And it's a good fit for a game like Wordy Findy.
There's absolutely nothing to it: just download the app (for free), choose a name to play under and just wait for the next game to start. Matchmaking is handled automatically. Once a game starts, players have around two minutes to find as many words as possible by tracing a line between connecting letters. Completed words earn points based on the values of the letters used and handy information like total available words and points are shown after each game. A scoreboard with each participant's name and score is also displayed between rounds, igniting those instinctual fires of competition while still providing the more humble with anonymity.
Wordy Findy is in the App Store right now, and it's completely free. Ad-supported with banners displayed at the bottom of the screen (mercifully out of the way), but still free.