Fiddler – Must Have for IE Development
// October 9th, 2007 // Technology Bits
If you do any web development for Internet Explorer, Fiddler is a must have application. Basically this is semi-equivalent to Firebug’s “Net tab”. If you have been using IE Developer Toolbar, this was a huge missing piece that can now be filled in.
Explanation of what it is from their site:
Fiddler is a Web Debugging Proxy which logs all HTTP(S) traffic between your computer and the Internet. Fiddler allows you to inspect all HTTP(S) traffic, set breakpoints, and “fiddle” with incoming or outgoing data. Fiddler includes a powerful event-based scripting subsystem, and can be extended using any .NET language.
Fiddler is freeware and can debug traffic from virtually any application, including Internet Explorer, Mozilla Firefox, Opera, and thousands more.
You should also check out the video tutorial.
2012 
Hi,
Fiddler is really an excellent tool.
You can also use DebugBar (http://www.debugbar.com) which gives all the http requests, grouped by page, with AJAX requests with a custom icon, and also a DOM inspector, a Javascript inspector, etc…
Hope this helps.
JFR
http://www.debugbar.com
Good tip, checking it out now. Thanks.
Hi,
I am happy to announce the release of Companion.JS version 0.2 with the “console.log”-Firebug feature under IE !
http://www.my-debugbar.com/wiki/CompanionJS/HomePage
Any comment is welcome to improve the extension on the next version !
JFR
http://www.debugbar.com
firebug is the best!