Magento: Event sales_order_place_before

config.xml

<config>
  <global>
    <events>
      <sales_order_place_before>
        <observers>
          <insurance_order_save_before>
            <type>singleton</type>
            <class>insurances/observer</class>
            <method>orderSaveBefore</method>
          </insurance_order_save_before>
        </observers>
      </sales_order_place_before>
    </events>
  </global>
</config>

Magento: Event sales_order_place_before

class PAV_Insurances_Model_Observer
{
  public function orderSaveBefore(Varien_Event_Observer $observer)
  {

  }
}