As Apple except its “Personal Hotspot” does not allow any other application to do unlimited tethering but any guy around with BALLS debuted it for $14.99 in the App store today. You just have to download it on your iDevice and one software on your MAC or PC to start it tethering.
Tether is an application that allows your Mac and PC to take advantage of your smartphone’s data plan, providing you access to the Internet on your laptop anywhere there is cellular coverage from your smartphone.
Tether is easy to install, easy to use, works practically anywhere, and is very cost-effective.
You need to install the MAC/PC application and the iTether app on your iDevice and you are free to go but beware that Apple can also remove it any time.