>> Would i just add another product line item on the bill and create a "Product" named Shipping?

Yes.

It would be Service product.  If they quote you during purchasing, add it there. 

I would also recommend adding a product called 'shipping' with no price on the PO so that when the Vendor Bill is created, it shows up ready for a price, or adding a product called 'free shipping' with no price if shipping is included (or even a product called 'rush shipping' with no price). 

This is because whoever creates the Bill is bound to want to know if shipping is or is not a legitimate charge (or if HIGH shipping charges are legitimate) - they probably will have no idea.  Think of this as saving your finance team from needing to call Purchasing to check each time a Bill comes in. 

I also recommend this for taxes also - a product called 'tax' with a price of 0.  Each of these lines communicates to Finance "Yes, we expect to pay tax. Yes, we expect to pay shipping".  Purchasing probably doesn't know the amounts, but they normally know IF those charges will be coming.