Interesting reading for the webheads out there is 14 rules for fast web pages:
Steve Souders of Yahoo's "Exceptional Performance Team" gave an insanely great presentation at Web 2.0 about optimizing website performance by focusing on front end issues. Unfortunately I didn't get to see it in person but the Web 2.0 talks have just been put up and the ppt is fascinating and absolutely a must-read for anyone involved in web products.