I've built out a site that looks great in FF and Safari.

http://dev.practisinc.com

Problem is, when it's viewed in IE 6 or 7 there are spacing problems with the logo and main nav. I'm using CSS image replacement for both the logo and main nav.

I've spent a lot of time playing with the margins and padding and can't seem to figure out whats going on here. It almost looks like FF is adding 4 pixels to the top of the branding area that IE isn't. But I have padding and margins zeroed out.

I'm stumped. Anyone have any ideas?