My ten year old has a hard time focusing?

we have been told that our son is bright however lacks organizational skills from kindergarden and up the main coment is lack of focus , he apears to be besome where else but when asked a question he is able to answer correctly,we are trying to limit his ds and computer time to every other day for roughly 1hour/2.when he is on those games he totatly zones in on them and it is a fight to get him off ,im looking into getting tested for a,d.dhis grade5 teacher doubts that is. lastyear he missed out on being on the alstar baseball team due to lack of focus i really need some helpin how to encourage him to focus and keep on track we tired various outlets drum lesson sports all the same comments he seems to just want to watch tv or vidio games please help