I need to send a copy of the order email to a particular email address every time an success order was placed. Is there way to configure this in magento without modifying or rewriting the sales order class ?
In your Magento Admin Panel, go to System > Configuration and in left tabs find Sales
Under sales select 'Sales Emails' , there in every tab and for every email type: order or invoice or shipment, there is option: Send Order Email Copy To write your desired email address here.
Select "Send Order Email Copy Method" if you want to send it as separate email or as BCC.