I've been invited to speak at the Dallas PHP meeting on Tue 21 Feb. The topic will be Solving the N+1 Problem. If you're in the area, be sure to come by!
UPDATE: Originally I had 28 Feb, but it's really 21 Feb. My bad.
Are you stuck with a legacy PHP application? You should buy my book because it gives you a step-by-step guide to improving your codebase, all while keeping it running the whole time.