First, kudos to Joel Birch for creating a wonderful menu plugin in Superfish, but I'm sure it's no surprise to anyone that what works fine in Firefox causes trouble in IE. In my case, it is simply the MouseOut being triggered prematurely in IE, so that the drop-down menu hides when you are still hovering over a menu item.
I have a very basic example at http://bb.allourbooks.com/1.11/ and would be eternally greatful if someone could point out why this IE malfunction is occurring. Thank You, -David Coon