Clever App for Keys and Transposition

Chord circle is a very simple iPhone app that is a reference for those of us who don’t have keys and modes like the back of our hand:

Modus

It also has a mode for easy transposing:

Transponering

Chord Circle is free and you can find it here: http://itunes.apple.com/us/app/chord-circle/id317325569?mt=8