First of all .. welcome to the BABB, reprise.
An internet search (google-yahoo-about.com, etc) is your best best. There are alot of sites that cater to youngsters, kidsastronomy.com is just one example. This is one such site with some solar system moon info .. here's one that might too much for an 11 yr old on his/her own, but has interesting stuff that a parent can help explain.