This past week people have shared apps which then lead me to even more apps. So I am going to pass on what I have found. These just happen to be iphone/itouch apps that can be played on the iPad and they are free. The company is called GAMeS Lab at RU and they have 12 apps but 10 are education based. I have not listed all 10 here, but you can find them in iTunes when you check out the app below.
Same Sound Spellbound: This is a game that helps you learn and practice homophones. The other apps you will find are also word and grammar based.