Since Netshare is banned by Apple on the App Store the only alternative you are left with is June Fabrics PDANET. PDAnet installs on jailbroken iPhone V2.x – 2.2.1. PDA net has not been officially approved on the AppStore yet, and it certainly won’t be.
On the iPhone PdaNet allows you to use your MAC or PC to access the device via WiFi and surf the internet wirelessly using your wireless data plan on the iPhone. Currently the latest version of the PDA Net app is v1.52.
How to install PdaNet?
Installing PDANet on your iPhone is very easy. You just need Cydia (that Comes via Jailbreaking) and search for “PdaNet”.
Your search for tethering solution ends here. App has a 14day trial and costs $29 for the full version.
Note: Tethering is not allowed by iPhone’s official carrier AT&T. This is the primary reason for Netshare / PDANet not being on the AppStore officially. Please review your contract with the carrier to ensure that you dont violate any of the terms.