Here is the article by Joel Webber with the good explanation of IE memory leaks.
Quote:
If you've ever built a really complex site using lots of JavaScript, you've probably seen this problem. You may even have some idea of where it comes from. Well, I'm writing this explanation because (a) I think I fully understand the problem and (b) there are a lot of confused (or simply wrong) explanations out there.
http://jgwebber.blogspot.com/2005/01/dhtml-leaks-like-sieve.html
I just want to add that the ActiveWidgets framework was designed to eliminate this problem and as I don't see any complains I assume it works.