Book of lairs
Awesome site, you get your weekly mail with "the latest" from other DM's. "http://newbiedm.com/":http://newbiedm.com/
is a site i stumbled upon the other day. great tutorial on how to make you own maps (still browsing the site).
The forge (Still looking for the url)
"http://www.wizards.com":http://www.wizards.com of course..