James Maliszewski has announced the Megadungeon.net website is up and running. Megadungeon.net is an "Old School" megadungeon project intended to produce a old-school megadungeon a bit at a time -- something like Monte Cook is doing -- except that this project is free and is based on the Swords & Wizardry (0e retroclone) rules set instead of 3.x. Of course, it should work just fine with Microlite74 or any other old school edition or retroclone.
James says "At present, what you'll find at Megadungeon.net is the structure on which the whole project will be constructed. There are maps, background information, introductions -- overview material, by and large. The "meat" of Urheim will start appearing over the next few days."
It looks good. I'll probably be contributing some small sub-levels to some of the lower levels: small pieces from my original Pyramid dungeon from 1976. Unfortunately, all I have left is a few sublevels that were printed in South Texas gaming club newsletters back in the 1970s. The original was lost sometime in the 1980s.