when you print out the <tr><td></td><td></td> </tr> tags in your while cycle,
check the row's number.
<?php
if($rownumber<=9)
$rowbg="#CCCCCC";
if($rownumber<=6)
$rowbg="#66CCFF";
if($rownumber<=2)
$rowbg="#99FFCC";
?>
after you have the background, print out the rows with the selected background.
<?php
while($row=mysql_fetch_assoc($results))
{
// here comes the $rownumber check
?>
<tr>
<td bgcolor="<?php echo $rowbg ?>"> </td>
<td bgcolor="<?php echo $rowbg ?>"> </td>
</tr>
<?php
$rownumber++;
}
?>
i know this can make with CSS, i suggest make it with stylesheets.