What the iPhone really needs is a product similar to
JoikuSpot that is available for the Symbian OS. Basically, it creates an ad-hoc network that you can then connect to from your laptop, etc and the software then connects you out to the Internet over the phone's 3G connection. No proxying, tunneling or other messing about, just connect as you would to any WiFi router.
Whilst this can't be done on the iPhone using the SDK, I see no reason why it couldn't be done for Jailbroken phones.
The other big thing that this has over NetShare is it runs in the background and is, in fact, a perfect example of an app that should be able to run in the background and which won't be helped by push notifications.
This is the sort of innovative development that is being stifled by the App Store controls