Tethering iPhone 3G is an excellent means to join to internet, when you cannot get a network installed in a particular place or when you are in a vehicle. iPhone 3G will serve as an internet modem for you in such circumstances. This special feature can be utilized only by the non-American iPhone 3G users, since in the US that cannot be utilized as per the legal clauses formulated by AT&T. If you are trapped using that in the United States of America, i.e. if you are customer of AT&T, you will have to face huge penalties.
Two ways are there to tether iPhone 3G, and they are, using a USB cable and using a Bluetooth.
For tethering iPhone 3G with USB cable, to start with you must touch 'Home' button on the iPhone. Next step is to touch 'Settings' icon and next to that 'General' tab and following this 'Network' tab. After that touch 'Internet and Tethering' tab and drop your finger till you reach 'ON'. Plug the USB cable in both, the computer, as well as iPhone to attach together. A Network Preferences window will come up, on which you have to click 'Continue' and then click 'iPhone'. Next, when you click 'OK', the setup will be finished.
To tether with a Bluetooth, initially touch the 'Home' key and further 'Settings' icon on the iPhone screen. After that touch 'General' tab and touch 'Bluetooth' tab. Move your finger across till you find 'ON'. Then, on your dock, click 'System Preferences' icon and following this for Mackintosh computers, click 'Bluetooth'. The boxes showing 'On' and 'Discoverable' have to be checked so that Bluetooth is enabled. Following this, in the application window, click '+' key and when the iPhone's name is found, click it. Next to that click 'Continue' and put in password on your iPhone, which you can get on the screen of the computer. Further click 'Start' and next to that 'Network' to set up Bluetooth for the computer. Next to that click 'Hardware and Sound' and then click 'Bluetooth Devices'. Pick up 'Add' and then check 'My device is set up and ready to be found.' Following this click 'Next', then 'iPhone' and 'Next' once again. The box of 'Choose a passkey for me' must be checked and after that click 'Next'. Your computer screen will show the passkey. Enter it on your iPhone and then click 'Finish', which will complete the tethering iPhone 3G with the help of bluetooth.