For those of you unfamiliar with the Montessori Method, just know that it's a highly successful and somewhat revolutionary way of teaching younger kids and is all the rage in major metropolitan cities. It seeks to enhance learning by catering to human tendencies and thus make it easier and more interesting for learning to take place.
To enjoy this application, you don't need to know anything about Montessori education outside of this: this application is the single best spelling application I have seen to date. Montessori Crosswords has won an Editor's Choice Award for Excellence in Design from Children's Technology Review. It as well has been featured in the New York Times.
This application teaches spelling using pictures, words and (most importantly) phonics; the sounds of each individual letter used in combination to form a word. The child then presses letters of the alphabet and hears what sound that letter makes and uses this sound to determine if it is the correct letter used in the word, or not.
As your child gets better and better, more difficult words using vowel combinations and consonant blends are given, allowing your child to learn to spell these more complicated sounds using combinations of letters. This app has rightfully earned praise from all over the educational community. I can't imagine a better way to promote literacy than through the use of phonics. This app NAILS it!
Compatible with iPhone, iPod touch, and iPad.