Loren Brichter, creator of Tweetie, the Twitter app that later became the official Twitter app for Mac and iOS, has just released a word game called Letterpress. The game is actually kind of fun, I've been playing it for some time now. It is strategy based, which makes it more interesting.
It consists of letter tiles that you choose to form words. Once you use the tiles, these turn either red or blue, depending of your color. You can steal tiles and turn them yours if you need to.
The game uses Game Center, so you can play with friends, or make new ones along the way.
Letterpress is available for free as a universal app (iPhone/iPad/iPod Touch) in the App Store [iTunes Link].