Speed up your web pages with YSlow a tool from Yahoo Developer Network

YSlow analyzes web pages and tells you why they're slow based on the rules for high performance web sites.

YSlow is a Firefox add-on integrated with the popular Firebug web development tool.

YSlow gives you:

* Performance report card
* HTTP/HTML summary
* List of components in the page
* Tools including JSLint

more info...