Internet Tethering on iPhone
In short, tethering is using a mobile device as a modem. Tethering is using a mobile device to gain Internet access for another device (ie: your computer, laptop, pda, or other mobile device). It works by connecting a device that has Internet access, to another device that doesn’t have Internet access. This can be done through Bluetooth wireless technology or cables, such as USB, allowing the device without built-in access to connect to the Internet, using the connected device as a modem.
The iPhone 3G and 3GS supports tethering, which is providing Internet connection through the iPhone to a computer or other device. This feature is useful when you are in a location where you can’t connect a computer to a network with Internet access, or you don’t want to spend money to do so, but can access the Internet with the iPhone’s high-speed cellular data connection.
NOTE: Additional fees may apply. Contact your carrier for more information.
Tethering works over the cellular data network. You can‚Äôt share a Wi-Fi connection to the Internet. If you have a 3G connection, you can make and receive phone calls while tethering.