Martha's right: the school's likely not to tell you if your son qualifies for special services. From their point of view, it's volunteering for more work. You have to walk a fine line here, between being a forceful advocate for your son while not aggravating the school system so much that they regard you as a "problem parent." My solution, which has worked fairly well, is to just never stop asking. I have e-mails for all my kids' teachers (they both have ADD) and when things get really bad (they do about once a year) I will cc the principal. (Don't do that too often--save it for when you really need it; if the principal isn't responsive, don't be afraid to take it up the line.) Assume, though, that the teachers are your partners until you get proof to the contrary (and some teachers still believe ADD does not exist).
Check to see if your son's school has an AVID program; it's not designed for ADD kids, but it can really help them.
Your son may need to be re-tested (diagnostic tests need to be done once every five years or so); check to see if his medications are the correct dosage (their bodies change a lot, obviously).
I've never had to fight to get my kids tested through the school system, because our insurance covered testing. But if your son needs testing, this is something they are required to offer you by federal law. The problem parents sometimes run into if their kids are really bright (and it sounds like your son is) is that the schools will say, "Hey, he's got a C average, he's not failing, what's the problem?" Doesn't matter. The law doesn't say "Kids must be flunking to qualify." It says "Kids with disabilities are entitled." Obviously there is some gray area there--there's no bright line between "normal" and "ADD"--but keep that in mind.
As for tutors: $30 to $40 an hour, and finding tutors who know how to teach ADD kids is a challenge. You can find tutors who know their subject but have no idea of how to deal with ADD kids. I am looking into a group in Severna Park called Learning Rx. If anybody out there knows about them, I'd be interested in hearing what they have to say.