Pocket Piano is exactly what it's title says it is, a pocket piano. This app turns your iPhone into a mini piano so that you can easily play any piano song you like anywhere you are. There are two versions of this app, one for $.99 and one for $2.99. The only difference is that the Plus version gives you 9 additional instrument sounds on the same keyboard.
Pocket Piano allows you to play up to 5 different keys at one time. It might be difficult to actually fit five fingers onto the iPhone, especially if you have thicker fingers. You also can't zoom out enough to really merit using 5 fingers that often. You can zoom in to a specific area of the keyboard if you want to make those keys a little larger.
You can also scroll around from left to right on the keyboard to get to different octaves. Just tap the screen and start scrolling. Tap it again to lock it. The most disappointing part of the app is the fact that you can't slide your finger across the keyboard and have it hit each note. It sticks on just the first note that you hit and that's all.
Both versions of Pocket Piano fall a little short on their own. There have been several apps that incorporate multiple musical instruments and give you the ability to record the sounds and play them back. Pocket Piano lacks these features and any other instrument. This makes it very difficult to justify purchasing either version. If the regular version was free, it would be worth a try for music fans.