In a game of now you see it, now you don’t, and now you see it again - iPhone tethering application NetShare is once again available via direct link in the iTunes store. No word on whether this will stay permanently or if it again will make a quick disappearance. This iPhone app allows users to connect some (but NOT all) programs on their laptop to the Internet by using the iPhone’s 3G signal. This process has been documented fairly extensively over on MacRumors with a “how to” guide - as well as some speed tests showing a 900k download and 200k upload speed. Before you get all excited, make note of this comment from the MacRumors forum — “when your iPhone goes to sleep or you exit the netshare application it will quit and your mac will have no internet access via your iPhone”. Looks like as long as your screen is active then you’ll be able to use the phone to power your laptop. As soon as it goes to sleep - so will your connection - making this really only a solution for very quick and desperate connections. Update: This application has once again been pulled from the iTunes App Store without explanation.

Netshare (direct iTunes link) via MacRumors