There's really not much about ADHD medications that this resource doesn't cover. It's a bit technical, but not so much so as to be overwhelming (though the length may be a bit overwhelming for some). I'm especially fond of articles like this that cite studies and which include a full bibliography in case you want to look the studies up yourself.

Great comprehensive resource into the many medications used to treat ADHD. Make sure you click on the medication chart (a PDF file), that includes generic and brand names, dosage and side effects.