I just got this today and while Ive only solved about 15, I can already give this 5-stars. Very nice user interface, one of the cleanest looking chess sets on the iphone. The puzzles are great, some were very challenging for me as a 1100 player (and Im only on 2 move mate, Im sure 4 move+ is going to be insanity). My end game is pretty rough, I have trouble seeing mates, if this is you, you need this app. It will teach you different mates and Im confident with practice you will recognize them in your games and help defend against a sudden check mate. This program gives you so much respect for these players and theres something cool about seeing the problems you face were historic games, not computer generated scenerios. The price is a steal at 99cents. I will probably buy the other chess puzzles this author has. 645 puzzles in total.
MuffinBottoms about Chess Puzzles: World Champions, v2.6