Hi,
First, you should update to the latest version which fixes problems with the shipping method not being added back to the cart once an address is entered/changed.
A shipping method is selected automatically if you the option "Auto select default shipping and payment methods" of the checkout tab of the configuration is turned on. You could turn that option off, or change your main tax zone to a zone where you don't ship to (you can for example create a zone via the menu System->Zones for that) and that wouldn't display any shipping before the address is entered.