It varies from hotel to hotel, but in my experience in the States, in room internet access is billed as a room charge. It appears on your bill with everything else. No need for credit card information.

Also, some hotels may have a different system in public areas. (like the lobby). For example, they may be a T-Mobile Hot Spot. If you already had an account with them, you would be all set. But just in the areas where that signal is available.

I would suggest a notebook with it built in. Since you want a PC based notebook, I suggest one that is Intel Centrino based.