You already have an Airport card, all PBs have come with them standard for awhile. When you get to your hotel room, click on the airport icon in the upper right hand corner of the screen and select the hotel network. Then open your browser. You'll either be on the internet at that point, or you will be at some sort of registration page for your hotel network where you may need to input your name, room #, etc. I'm not sure if you'll have to change any internet settings in System Preferences or not....
Bluetooth is a wireless connectivity technology for periferals (wireless keyboards, mice, printers, cell phones, PDA's, etc). Your PB has Bluetooth, but this is not used for internet access.