I don't know if this is the case for your site (I am too tired to look through your stylesheet right now), but I had the same problem and figured out why.
If you have something like
and your content text is longer than the overall frame, it will overlap and leave a gap of sorts. What I think happens is that the browser computes what 100% height is before it enters in the content. When the content is finally put into the layout, the length of the frame is already set.
confused If you try un-nesting some layers, it might work out for you. Sorry it is so hard to explain. This is why I don't make tuts or ever tutor.
sweatdrop P.S. It seems to display fine in my Firefox, but I know how that goes. Also! Your site is in my school's colors
whee