I have been searching for this and others have had this problem, but the solutions have not worked for me so far.
My site is http://www.myeyespy.com/bcc
I am using a plugin for the random picture in the sidebar - lazyest gallery. Everything works fine in Firefox, but in IE then I get the contents of the sidebar moving down to below the vertical position of the articles in the main text.
The strange thing is that this only happens sometimes - you can hit refresh and then the next sidebar contents will show at the top of the page correctly. Hit refresh a few times and you will see what I mean.
You would think this is to do with the size of the picture - but they are all set to be a maximum size using the gallery plugin. I attempted to change the thumbnail size to being just 50 pixels and it would still randomly work/not work.
Also on the times that it works fine, then it is often with a wide picture (width>height), and other times it does not work with a tall picture (height>width).
So it is a bit weird.
If anyone has any ideas then I would appreciate any pointers.