solveKlotski will visually solve any Klotski or ‘Sliding Block’ puzzle you throw at it. You’ll get a step-by-step solution in the form of PGM image files. Just add your own Klotski puzzle to puzzles.h and you’re good to go.

Download it from here:
solveKlotski v4

If you have no idea what a ‘Klotski’ is, maybe this animated GIF will give you an idea (click to see it in action):

You may freely use solveKlotski and it’s source codes under any terms you wish. The inspiration and motivation for this came from one of the excellent Professor Layton Games for the Nintendo DS.