Shipping Quote option

Is there a way or an extension that would allow the following to happen...
A customer adds items to their cart.
Instead of going through the checkout process right away, I would like the order to come to me so I can calculate the shipping charge - then let the customer know what the shipping charge would be, and them to be able to add that quoted shipping price to their cart and then continue through the checkout process.
I have searched and cannot find anything that helps.... is this even possible?

Thanks for any suggestions / help.

DJ