I started out a little worried about this resource, as it seemed to imply that you must exhibit symptoms of both hyperactivity and inattention to be diagnosed with ADHD (this isn't true, as one can, for example, have ADHD--inattentive type without being hyperactive). Reading further, though, this article got better and better with a lot of good information about symptoms, diagnosis, and treatment.

This contains just about everything a newcomer to ADHD should know; a good overview even if somewhat short on details.

Really comprehensive and informative. It's long, but it's worth the read, particularly because I found the last few sections to be the most interesting. I always find a lack of mention of ADHD's overdiagnosis to be somewhat irksome, since we're living in such a diagnosis-happy society, but I'll let it slide this time. This is a great article.