I have done it, but it only works with IE. Netscape doesn't support dynamic changing of the background color of a table cell on a onmousover event (at least not that I have found). Incidently, this code also changes the cursor to a hand (like when you mouseover a link)... for example (sorry, it is straight out of my code, so it is a bit messy):
in the style tag in the <head> tag:
.offstate {
background-color : #CCCC99;
}
.onstate {
background-color : #FFFFCC;
cursor : hand;
}
in the body:
<tr class=offstate onMouseOver="this.className='onstate';" onMouseOut="this.className='offstate';">
<td>Some stuff in the table</td>
</tr>