Here's a great Internet Explorer plugin that will help you track down a variety of IE problems.
The DebugBar V4.02 is an Internet Explorer plug-in that bring you new powerful features :
* DOM Inspector: View DOM Tree and modify tags attributs and css attributes on the fly to test your page
* HTTP Inspector: View HTTP/S request to check cookies, GET and POST parameters, view server info
* Javascript Inspector and Javascript Console: View javascript functions for easier debugging, see Javascript and AJAX code
* HTML Validator: Validate HTML code to correct and optimize your code and html size of your page
* And many more features: See page cookies, get pixel color on a page, make a page screenshot...
from http://www.all4you.dk/FreewareWorld 
