KidsSave is a kid-centric application (Windows XP only, with an OS X version coming out next year) that lets your child track allowances and other types of “income” and teaches the benefits of saving.
Parents can set up interest rates or matching payments, and kids can play around with the “what if” tools to see instantly how much they stand to earn over 1, 2, or 10 years if they keep saving. It’s not free ($30), but there’s a 35 day trial period on the software, so you can give it a full test run. At the very least, you might feel inspired to set up your own Excel chart for your kid.
“Personal Finance: Teacher gets kids to play and save” [Sacramento Bee]