I use this from time to time to see how fast (or slow) my sites` pages are displaying.

http://www.websiteoptimization.com/services/analyze/

Free Website Performance Tool and Web Page Speed Analysis

Try our free web site speed test to improve website performance. Enter a URL below to calculate page size, composition, and download time. The script calculates the size of individual elements and sums up each type of web page component. Based on these page characteristics the script then offers advice on how to improve page load time.