If you're interested at all in 4th Edition, go check out Mike Mearls's forum blog. And the other 4th Edition staff forum blogs.
There's some good stuff in there, and not just about 4th edition. What really caught my eye was this piece on making dungeons "chunkier," that is, keying encounters to groups of rooms rather than single rooms. That way it's easier to keep track of what's going on in each room, and how they're interacting. Good advice, no matter what edition you're running.