Playing Capture Go is an excellent way for beginners to learn about the tactical fundamentals of Go - the first player to capture a stone wins! It can be one of the first steps after learning the rules of Go, using some simplified rules shown here. It's really quick to finish a game.
There is an app for the iPad and iPhone at a cost of £1.49 called GoforKids which is purely for Capture Go (3 levels). If you can't find it in the App Store, you can find it via http://go-for-kids.appspot.com which also includes instructions! It is probably a good idea to read the instructions before using it anyway!
To start, click on the play link below to open a new window.