D&D Classics went live today. In case you don't know, it's where WotC is selling PDFs again. It's an DriveThruRPG/RPGNow affiliate, so you can use the same login information. There's PDFs available from AD&D, AD&D 2nd edition, D&D 3.X, and D&D 4E, including stuff from Greyhawk, Ravenloft, Eberron, Forgotten Realms, and Planescape. I expect they'll be adding more content in the coming weeks.