I use
http://www.websiteoptimization.com whenever I have a problem with a slow loading site, and it pointed a ton of things out
You have 56 unique images on the index page, and you load images/scripts/iframes from a total of 8 foreign domains
The uncompressed html of your index page, not including the pages you include via iframe is over half a megabyte. That's just the html. My firefox almost crashed just trying to copy that from view source.