<style>
td.renk1 { background-color:#ccc; }
td.renk2 { background-color:#eee; }
td.renk1:hover { background-color:#ddd; }
td.renk2:hover { background-color:#fff; }
/* Anchor içinde benzeri olur */
</style>

<?php
$renk_counter = 0;
while($yaz=mysql_fetch_array($sor)){ 
$id=$yaz['id']; 
$baslik=$yaz['baslik']; 
$hit=$yaz['hit']; 
$tarih=$yaz['tarih']; 
$katid=$yaz['katid']; 
$katcek=mysql_fetch_array(mysql_query("select * from kategori where id='$katid'")); 
$katadi=$katcek['katadi']; 
 echo "<tr> 
    <td><a href=makaleoku.php?id=$id>$baslik</a></td> 
    <td>$tarih</td> 
    <td>$hit</td> ;
if ($renk_counter == 2)
    <td class="renk1">
else
    <td class="renk2">
<a href=kategori.php?id=$katid>$katadi</a></td> 
    "; 
     $renk_counter++;
if ($renk_counter == 3)
$renk = 0;
    }  
?>