Tess: I was helping a colleague with an interesting case yesterday concerning a memory leak in IE when using winforms usercontrols.
We got a nice little repro with a very basic user control that displayed a picture and each time the page was refreshed it appeared to leak quite a bit of memory,
and inducing a garbage collection had no effect on the memory.
I started off with setting it up on my machine, and then I used Debug Diag 1.1 to track down the leak... Debug diag is not all that great for managed/.net memory leaks since the GC manages the memory for you as I'll show later... but I figured that since I had a repro it was worth a try...