Copy the core file from this location..
app/code/core/Mage/Sales/Model/Quote/Address/Total/Shipping.php

and put this file to your local code pool..

app/code/local/Mage/Sales/Model/Quote/Address/Total/Shipping.php

Search this function "public function fetch" on the file and replace this text.
$title = Mage::helper('sales')->__('Shipping & handling'); // Original
$title = Mage::helper('sales')->__('Shipping'); // Replace