I watched the video ADD & Loving It?! on PBS last night. It was great. Funny and full of insights. Not perfect, but sure worth the watch. The best part is that Rick Green (you might know him from The Red Green Show) describes how ADD feels for him, as do several other adults. This is more geared to adults than children, although probably teenagers could find this video useful too.
It is easy to see how the hyperactive components of ADHD - the impulsiveness especially - are similar to the symptoms of mania. No wonder there's confusion!
I actually don't have ADD. I did take Ritalin at one point, and while it helped for awhile, I just don't have the ADD symptoms on a continual basis. My attention problems come and go depending upon my mood. When my mood is doing well, my attention is fine.