Here are some of the tools that helps to optimize/analysis our websites speed.

1. Page Speed – Could be found in Google's webmaster tools page, it's a Firefox Add-on that evaluates your web page performance and suggests improvements.
2. Firebug – It's a Firefox Add-on that I used along with page Speed. It lets you edit, debug, and monitor CSS, HTML, and JavaScript after
3. Yahoo! YSlow – A Firefox Add-on that works like Google's Page Speed. It analyzes web pages and suggests ways to improve their performance, based on a set of rules for high performance web pages. Works best when integrated with Fire Bug.