Magento : Inject custom module block to other modules

Magento inject custom module block to any module code sample



<firecheckout_index_index>

       <reference name="checkout.onepage.review.info.items.after">

           <block type="sendfriend/send" after="media"  name="sendfriend.send" template="sendfriend/send.phtml" />

       </reference>

   </firecheckout_index_index>