Despite AT&T's lack of tethering services for the iPhone 3G, a group of intrepid developers has produced a viable method for using the phones as wireless modems for laptop or desktop computers. Note, however, that the process requires iPhones to be "jailbroken" (allowing unsupported read/write access to the filesystem) and stands in violation of AT&T's data plan agreements.
The basic process is as follows:
- Jailbreak the iPhone
- Install the applications 3Proxy and Terminal via Installer
- Create an ad-hoc Wi-Fi network using your computer
- Join the ad-hoc network from your iPhone
- Find the iPhone's IP address (tap the arrow next to the name of the Wi-Fi network to which your iPhone and look at the IP Address)
- Use the Terminal to run the proxy program on the iPhone
- Open Safari on your iPhone and navigate to any page
- Configure your computer's browser to use the proxy
Complete steps are available here. Extended tethering use can drain the iPhone's battery fairly quickly; as such, users should keep the device powered via a USB cable while tethering. Also, note that AT&T could cancel or sanction your service if your account shows inordinate data transfer quantity.