Sometimes finding that perfect chord is more difficult than just putting your fingers on the strings. On the iPad, you can use ChordMate ($4.99) as a digital chord book. As you would expect, ChordMate gives you the names and fingering position for the most popular chords and some of the less common ones too.

The customizations in ChordMate are very cleverly done. For instance, when you start typing in the search box, a list of chords pop up. Another cool feature is the custom keyboard—it has the major chords, numbers and special keys for "sus," "maj" and others. That allows you to quickly enter in chords with a kind of built-in shorthand.

You can set alternate tunings and play the chord sounds using a classical, acoustic, or electric guitar.