Take advantage of having a backup internet connection on iPhone 3.0 and utilise Internet Tethering without the need to pay Your Network an additional amount a month on top of your existing data connection charges.
Fear not humble iPhone users, there is a solution out there. Browse to this URL from Safari on the iPhone:-
http://www.iphone-notes.de/mobileconfig/
Select your country and carrier, and download the Tethering profile (ignore the warning message)
Note: This doesn’t mean you get data for ‘free’, but if you already have a ‘data package’ it should be included within that, rather than paying a separate ‘Tethering’ charge (like O2 the £14.99/month are trying to get you to do in the uk !)
When you go back into Settings, General, Network you will now see that the Internet Tethering is ‘Off‘ (as opposed to ’set up’)
If you now tap on the “Internet Tethering“, you get a new screen that allows you to enable it
When you have this enabled the you can share the internet connection from your mobile and use over bluetooth or usb cable with other devices..