"I Write Words" is a great app for developing handwriting skills. I personally think it is one of the best choices for preschool writing that I have tried. It is fun and appealing to 4 year olds. It really teaches and helps the kids develop eye/hand coordination while learning correct letter formation. The settings also allow you to make it more challenging as the child's abilities progress. You can practice individual letters and numbers, or practice writing simple words. The children especially love tilting the ipad to get the letter blocks to go into the "vortex" when they have successfully completed each letter or word. There is also a free "lite" version to try it out first.