QuasiDisk was a little gem that made it into the iOs App Store several months back. If you weren’t able to purchase it then this review / tutorial won’t be much use to you.
QuasiDisk is a simple app with a hidden function that allows you to tether your iPhone to your computer for internet on the go. This is not a jailbroken app. Though it works perfectly it takes a few steps to setup so it’s not for the faint of heart. Skill level beginning / intermediate