Your laptop maybe wireless enabled already. If you post the make and model here, we can tell you. Otherwise you will need to buy a wireless adaptor. This can come in the form of a card that you can slot into the side of the laptop, or a wireless USB adapter that will plug into one of the USB ports on the laptop.
Once you have one of these (if the laptop is not wireless capable already), you could then find a 'WiFi' spot and use the internet.
A good number of major hotels now have WiFi spots within their bar areas.