oh I see..
<td onmouseover="this.childNodes[0].style.textDecoration='underline';" onmouseout="this,childNodes[0].style.textDecoration='none';" ...
or something like it would work... but then, when you click on the cell, it wont go to that href. A simpler way is to make the anchor span the complete width and height of the cell.
<td....><a style="display: block;"..>..
I think should do it..
if not:
<td...><a style="display: block; width: 100%; height: 100%;"...>...
Tell me if any of that works, I'll help you out with the details afterwards

you might wanna check this out:
http://css.maxdesign.com.au/listutor...tal_master.htm
it does what your doing, but without a table... much less messy code. it's css based, anyways, hope I could help a bit.
edit: I went to test a couple things..
best way to do it really is to give an id to the tr that contains your links, let's say id="navigation"
then in your stylesheet:
#navigation a { display: block; }
#navigation a:hover { text-decoration: underline; }