/* ---CSS STYLE--- */
tr.sudy td {background:red}
tr.lichy td {background:blue}


/* ---PHP--- */

$lichy = true;

while(($row = mysql_fetch_row($result)) !== false) {

    echo "<tr class=\"".($lichy?"lichy_radek":"sudy_radek")."\">";
    echo "<td>".$row[0]."</td>";
    echo "<td>".$row[1]."</td>";
    echo "</tr>\n";

    $lichy=!$lichy; //zmena priznaku lichosti

}