The IE6 a:hover Bug Fix Tutorial
Here is a working example.
IE6 has a bug in it that prevents it from showing a hover effect on a rule like "a:hover img" unless a particular change in the hover state is also applied to the "a:hover". I personally, like to use a:hover{visibility:visible;} to cure this bug because it changes nothing! I've listed a few other rules that also cure this bug in the above example's source code. However, there are many other rules that work as well.