I'm volunteering with a group of 1st graders who are doing Study Island for half an hour every day. They're on the 2nd grade level so it's giving them an opportunity for some subject acceleration. When they have trouble with a new concept, I can give them a quick explanation. The kids seem to love it and are able to work at their own pace. This also gives the teachers time to work with the other students on more basic concepts. So far, so good!
P.S. I'd ask your son about the level of difficulty. If it seems too easy for him, I'd ask to have his level raised.
