Three colums displaying different betwee IE and firefox/netscape

At my site (www.motorcitycrossfit.com) I’ve got a 3 column layout, but for some reason am having trouble resizing (and properly placing) the right and left sidebars on all browsers, without screwing up where the center column ends up.

In short, in Firefox/Netscape, it shows up good when I resize the right, I figured out how to get the column to shift over to the right. But with the left, the same thing doesn’t work. No big deal, I can live without resizing the left.

But the same setup in IE shifts the right column over to the left (like 129 pixels, the difference between the original size and the new size), and this causes the center column to not display correctly at all, and in fact it actually displays the left and right columns towards the top of the page, and then starts the center column at the bottom of the page after the left and right columns are done.

Look at the page in both browsers, I think you’ll see what I mean. But problem is, I haven’t a clue how to fix it so it works with both browsers.