<config>
<global>
    <models>
        <mss_sunrise>
            <class>Mss_Sunrise_Model</class>
        </mss_sunrise>
    </models>
</global>
<crontab>
     <jobs>
        <mss_sunrise>
                    <!--<schedule><cron_expr>0 1 * * *</cron_expr></schedule>-->
            <schedule><cron_expr>*/10 * * * *</cron_expr></schedule>
                    <run><model>sunrise/observer::updateproductprice</model></run>
        </mss_sunrise>
       </jobs>

class Mss_Sunrise_Model_Observer

  {
public static function updateproductprice()
{

Mage::log("WORKS!",null,'cronjon.log');
}}