I'm using the latest version of Xampp, developing my store
on the localhost and everything appears to work correctly except
the Estimate Shipping and Checkout functions from the Cart.

About half-way through loading the popup for shipping it pauses
indefinitely, while hitting the Checkout button doesn't even
get 1%... all it says is 'Waiting for localhost'.

Btw Xampp doesn't include cURL, for which the warning on
installation informed me - would this have anything to do
with it? As I remember the installation I did with ByetHost.com
went about the same, and it worked there.