NetShare's inclusion in the App Store is a curiosity, as Apple must have manually approved its inclusion. It's unclear if the Application would go against AT&T user agreements. AT&T typically charges Smart Phone users $30/month extra to use tethering applications. Screenshots of the application's instructions have been included here:
This application has been confirmed to work by multiple users. NetShare is available on the iTunes App Store. Update: The application appears to have gone missing from the App Store. While the application listing still appears, if you try to purchase it now, iTunes says "The item you tried to buy is no longer available".
Update 2: For those who were fortunate enough to get the app, forum user Mac-Addict has posted a detailed tutorial.
Update 3: Developer reply: It is not clear yet why Apple took down the application yet, we've received no communication from Apple thus far. NetShare did not violate any of the Developer or AppStore agreements.