I have some great news for you, iPhone users. If you thought that MyWi allows you you to tether your iPhone at a reasonable price compared with what AT&T offers, well you are absolutely right, but I have to inform you that there is a cheaper way.
MyWi is quite popular nowadays, but I think TetherMe with a price ten times cheaper will be the rock star soon enough. TetherMe is available on Cydia for only $1.99. MyWi can be purchased from Cydia too, but for $19.99. Unlike MyWi, TetherMe can only support tethering on iPhone only. If you are using iPad 3G, do not install this app because TetherMe does not work with it yet.
TetherMe: Native tethering for your iPhone
TetherMe enables native tethering for all iPhones from iOS 3.x up to iOS 4.0.1., and it should work on any carrier without anything changed. TetherMe allows you to carrier bundle manually by bypassing signature checking. This is also required for MMS functionality on T-Mobile. This app does not enable the loading of APN configuration, meaning that your carrier will not charge anything extra. You can find TetherMe on Cydia under BigBoss repository. After you’ve purchased and installed the app, reboot your iPhone and then navigate to Settings –> General –> Network for enabling or disabling it.