Just wanted to let you know. Some of us play with kids, and while I haven't used this ruleset with kids I know from a friend who plays with his 4-year old. I've actually used this as a light-weight rules set for grown-ups to show them what P&P role-playing is. The system is easy to adjust to pretty much any setting and I think it might be worth mentioning that several translations exist, too.
I have this system. I've used it running a game for my daughter (8/9 yo at the time) and my wife. It's really alot of fun, and the adventures are great too for youngsters/those new to the gaming. Each adventure has pages of printable maps and paper standees for the locations/monsters, if you like "minis"
Frankly, I think it would work fine with a bit of tweaking for a easy fast RPG for "kids" of any age.