"it's official, this is the best thing on the internet, ever." Let's Play Ukelele skims your last.fm tags, works out which songs or bands you like are the easiest to play, and gives you the tab and the chords. Delightful.

Or, more specifically, a few jazz chords for guitar. Some nice reference on this site, particularly for other tunings such as DADGAD - not the best by a long way, though.