iPhone internet tethering allow you to use your iPhone as a modem. You can use it to connect your laptop to the internet if you are not able to find a Wifi Network. Tethering is not available in all countries but we can use it here in Singapore.

To turn on Internet Tethering on iPhone
Go to Settings/General/Network/Internet Tethering and turn internet tethering on.

The laptop must have iTunes 9.2 or later install on it. You just need to follow the instruction  for the setup on your laptop. You may also refer to the Apple internet tethering troubleshooting guide by clicking here>>>