A million people can’t be wrong! If you like Guitar Hero and have an iPhone (or iPod Touch) this game can seriously pass some time… and its free.
The object of Tap Tap is to tap on the beats as they come floating down your screen. There is an option to either play solo or a 2 player game. The free download comes with 4 songs and you have the option to download more to keep the game interesting. Here is a video of it: