Mystery Word Town is a great app for practicing spelling, embedded into a really fine mystery solving game.
Travel with the ghost sheriff in a ghost town. He's looking for bandits and outlaws who have stolen gold and are hiding out in abandoned buildings within the town. Each building is a new search for an outlaw, and each door provides a mystery word to be spelled for unlocking.
Spell words, find gold and capture the outlaws. That's the name of the game!
The app was created ostensibly for older children, but I found my two year old daughter quickly formed a liking for the characters and music. She can't spell herself (still needs daddy's help) but I think it's worth mentioning that this app got her interested in words and spelling.
There are many benefits available from this app. It promotes learning with spelling and provides a generous amount of practice. There are three skill levels and two game modes for flexible learning. The app design inherently promotes critical thinking and problem solving.
Compatible with iPhone, iPod touch, and iPad.