problems with cross-browser layout css

[grayceworks]

My site works lovely in Mozilla and Firefox.

http://www.villadec.com

However, get it in various versions of IE, and it looks odd.

In IE 6, on the main page, which holds the category listings, and on sub-category pages, such as the "Lamp Shades" or the "Hand Painted Porcelain" pages, the list of categories goes below the box that is supposed to hold it.

see:
http://www.villadec.com/images/IE6screenshot.gif


also

In IE 5, on the main page, the categories instead of being three in a row, the third one drops down to the next row.

see:
http://www.villadec.com/images/IE5screenshot.gif

Also in IE 5, on the product listings pages for each category, the listings box extends out past the right edge of the layout, rather than staying the same width it was on the main page.
see:
http://www.villadec.com/images/ie6-2screenshot.gif

I have gone through my css and am pulling my hair out trying to figure out where it's messing up, but I can't find what's making the difference between IE and Mozilla.

HELP???


any other input is appreciated as well...