Some of you may not believe this, but the Gamemaster's Guide for Pathfinder is an excellent resource for OSR DM's. The majority of the book is either descriptions or self-contained systems for things like city creation. I bet only 20 pages or so are stats for PF characters, and even the ideas included with those NPC writeups would be useful to many DM's. Anyways, I recommend it for those of you looking for a big book of advice on improving your game.
It would be nice to see an OSR DMG similar to this. Or that combined the best of this book and the 1e DMG.