Dragon magazine is a magazine for roleplayers. It's been around a long time. I haven't picked up a copy in many years (like 10 or so) but I recall that it used to be completely oriented around D&D. They used to always have an adventure for DM's, short stories, and suggested modifications to the AD&D 2nd edition rules (like new classes etc.).
I also think there is a link on the WotC website that has the information you are looking for, although it may have moved since publishing of Dragon Magazine has now fallen to a different company.