There’s have been quite a few ways to use your iPhone as a Modem. Earlier methods were cumbersome and too complex for normal users.
Then came an easier way, an app called NetShare was launched which made things very easy.
I had also posted a Tutorial to Use your iPhone as Modem via the NetShare Application.
But NetShare was not a free application. An alternative to NetShare has just been released and is now available via Cydia !
The Application is named simply as “iPhone Modem” and promises to tether your iPhone within just 10 seconds !
I haven’t personally tried it yet, but from what I heard it works just as advertised and easy to use !
Get it now from Cydia.
About those wondering what Cydia is, Cydia is a AppStore like Application. You need to JailBreak your iPhone.