If you are a web developer you might be familiar with the great free tool - Firebug.
Firebug is an add-on for Mozilla Firefox that allows you to easily inspect the HTML
DOM/CSS for a page, edit them inplace and many other useful tricks. Recently
I came across another useful tool YSlow -which
is an addon to Firebug. YSlow is from Yahoo! which analyzes web pages and tells you
why they're slow based on the rules for high performance web sites. Check them out!
Read the complete post at http://www.venkatarangan.com/blog/2007/09/14/Firebug+And+YSlow.aspx