Well, the only problem I encounter is a Flash of Unstyled Content. Maybe you should edit your link rel. It ends "/>, which needs to be " />. And just because I love it, it's XHTML 1.0 Strict too, so it's nicer to set your doctype to strict. Just an addiction
I suspect (with only a little bit of proof) that the frames are the source of your problem in IE.
I experienced the same "flashing content" problem that was described before and I also experienced some REALLY weird image tiling that was unlike anything I've ever seen.
I pulled a few pages out and played with them locally on my machine. When I removed the frames and viewed the files linking to each other in IE there was no problem at all...
Another note, I stubled across the tag <br></br> in your code. That tag is self closing so you might try <br /> instead. In IE it recognised <br></br> as 2 break tags (???) and gives an extra space between lines.
Hope that helps solve the IE problem.