The item you've requested is not currently available in the U.S. store.Sounds like people in other countries may still be able to get the app. On the other hand, Nullriver, developers of the app, don't even list it on their site.
NetShare was priced very reasonably, at $9.99 before it was pulled. Some people managed to get their hands on it, and posted some detailed instructions on use. Not that it really matters, as no one else can get the app (and despite pleas for it, no one --- at least not in that thread --- is willing to share it). Of course, it might appear on P2P soon ...
Update via Nullriver's website:
We're not quite sure why Apple took down the NetShare application yet, we've received no communication from Apple thus far. NetShare did not violate any of the Developer or AppStore agreements. We're hoping we'll get some feedback from Apple today. Sorry to all the folks that couldn't get it in time. We'll do our best to try to get the application back onto the AppStore if at all possible. At the very least, we hope Apple will allow it to be used in countries where the provider does permit tethering.