You can use iPhone 3G or later as a modem to connect, or tether, your computer to the Internet. You can connect iPhone to your computer using the Dock Connector to USB Cable, or via Bluetooth.
NOTE: Additional fees may apply. Contact your carrier for more information.
Tethering works over the cellular data network. You can’t share a Wi-Fi connection to the Internet. If you have a 3G connection, you can make and receive phone calls while tethering.
NOTE: To use iPhone as a modem with a Mac computer, it must be running Mac OS X version 10.5.7 or later.
In Settings, choose General > Network > Internet Tethering.
Slide the Internet Tethering switch to On.
Connect iPhone to your computer:
USB: Connect your computer to iPhone, using the Dock Connector to USB Cable. In your computer’s Network services settings, choose iPhone.
On a Mac, a pop-up window appears the first time you connect, saying “A new network interface has been detected.” Click Network Preferences, configure the network settings for iPhone, then click Apply. On a PC, use the Network Control Panel to configure the iPhone connection.
Bluetooth: On iPhone, choose Settings > General > Bluetooth and turn on Bluetooth. Then refer to the documentation that came with your computer system software to pair and connect iPhone with your computer.
When you’re connected, a blue band appears at the top of the screen. Tethering remains on when you connect with USB, even when you aren’t actively using the Internet connection.
In Settings, choose General > Usage.