In your current template's stylesheet, find:

Code:
#navMain ul, #navSupp ul, #navCatTabs ul {
line-height:0.4em;
list-style-type:none;
margin:0pt;
padding:0.5em 0em;
text-align:center;
vertical-align:top; }
Perhaps, try lessening the value(in red) to say... 0.3em ?
Give that a try and see how IE renders it.