CSS hover problem with links in IE

I'm at my wits end with this really. My brains fried, hopefully I can find some help here.

My links display correctly in Firefox but IE is giving me fits. When you hover over the link, the font size of the anchor text increases a bit and gives sort of a 'jump'. I tried defining a specific font size for the a: attributes that matched the font size of the div it was in but that only botched them up further in both FF and IE by shrinking the text. I've gone through the css many times and validated it and I'm not seeing where I screwed up, maybe someone here can.

CSS - http://www.givesgoodaural.com/includes/layout.css
Page - http://www.givesgoodaural.com/test.php (view in IE to see what I'm talking about)

Any help is greatly appreciated. The problem occurs after the #nav div (the menu underneat the logo) and continues on to the footer div. the two columns are #splitcol-left and #splitcol-right which are nested inside #wrapper

 

I've sorted it out, it was using .em for font sizes that was throwing things off. There's still a small glitch in my last.fm list but nothing serious. Thanks to anyone who took the time to read.

As an aside: I didn't realize you could use float:none as a means of centering, works pretty well!

 

float: none doesn't center an element, it's something in your document that's doing it

You usually use margins: margin:0 auto;
Or the text-align property: text-align: center;