Google Webmaster Tools is currently providing a Site Performance feature in Webmaster Tools. This feature delivers two pieces of information:

• Performance overview: how long it takes your site to load (measured in seconds), how this compares to other sites, and an assessment of this measurement’s accuracy based on the number of data points.

• Page Speed suggestions: suggestions on how to optimize pages from the site based on the Page Speed tool. Google not only provides these suggestions, but also an estimate of the potential improvement in file transfer size or speed if implemented.

A Page Speed browser add-on is also available here to evaluate page performance and provide solutions for improvement.

One thing to note: Google includes a disclaimer that Webmaster Tools Labs features may change, break, or disappear at any time.  Hurry up and check it out.