Noah Witherspoon has released Tris [App Store], a free version of Tetris, for the iPhone.
Touch controls move pieces left, right, down and even up, while tapping allows you to rotate your piece. The actual game is nicely implemented with attractive graphics and smooth animation. Tris also offers a global high-score system so you can compare your play with others. A lack of sound effects or music, however, makes the gameplay a little unsatisfying. Fortunately, you can play your own music in the background.
Still, it's hard to complain about free. Witherspoon's game has already hit the #1 spot in the App Store. Download it in the App Store.