depends on your browser
mozilla (and probably NS6) should let you do this:
in you stylesheet
them any td with the classname 'myclass' will change to red when hovered over
It doesn't work in IE6 or opera6 on the PC.
If your options are links though you may find this useful:using CSS to create rollovers
which might help you re-create what you need.
or use creoles suggestion, it'll work but it's not *pure* css