Recently I discovered a problem with viewing my blog in IE. It seems that my entire left sidebar had dropped to the bottom after my last post.
Imagine my surprise! Not exactly the look I was after. Since so many people still use IE, I had to get it fixed. After much research (and ado) I found I wasn't alone. They even had a name for this little oddity - float drop. I found out the cause of my 'float drop' was an image in this post, Customizing your header: make your own banner, that was too wide for the post area. My suggestion if you encounter this problem is to look at your posts for wide images. Long URL's can do it also. Check both the posts and the sidebar for oversized items.
Jon Aquino's Mental Garden
...Internet Explorer problem called float drop, in which if the main column and sidebar column are too wide to fit side-by-side...
If this doesn't cure it for you, I found other ways by editing your template. Fixing "Float Drops" in the Blogger Templates gave some insight into how to accomplish this. Luckily I didn't have to go that far...a simple resizing of an image, and I was back in business.