A while ago I bought this App: http://www.macrumors.com/2011/11/29/itether-app-offers-inter...
Best $15 I ever spent on an App, because Apple pulled the App shortly thereafter, and I have unlimited data.
It uses the same sort of technology ... having a web browser open on your phone within an App that provides a tunnel. You have to have the App open on your phone and on your Mac/PC.
However, there's one downside: You need to have the App foregrounded on your phone, regardless of method, due to the fact that I believe WebSockets are inactive when backgrounded on iOS.
The App still works on iOS 7.