A and I have just discovered PBS Kids Island
at PBSkids.org. It is a set of free games that teach reading skills. The system requires an email account and multiple kids can play under one email address. A parent / caregiver can check the account to learn a little about what their child is doing.
My feelings are mixed. A seems to like the games, but he was frustrated that more buildings are not on the island (after mastery of one area, new areas are added). I'm concerned about spending a lot of time online, although A has been free to play games at several kids' network sites.