For this i use the "<!--[if IE]>" directive, for example:

   <link rel="stylesheet" type="text/css" href="./style.css" media="screen" >
   <!--[if IE]><link rel="stylesheet" type="text/css" href="./IEstyle.css" media="screen" /><![endif]-->

Classes in the IEstyle.css style sheet are declared after the default style and thus override any options previously defined.

so if in style.css you declared:
   height: 100px;
and then in IEstyle.css:
   height: 200px;

You would end up with IE using the height: 200px; and all other browsers using height: 100px;

I am aware of other methods such as javascript and some crazy "/*\*/" css hack. But i prefer this one.
Hope this helps.

edit: also you can find an example at my site in progress, nullam.net

If you include the conditional IE statement after the CSS you use for all other browsers, then your IE stylesheet need only include the styles you want to add to, or override, in the other style sheet.

If you only have a few differences you can use the underscore hack: