John Brownlee at CoM:
“It seems likely, then, that as soon as the Verizon iPhone comes out, Apple will pump an official iOS update for all devices down the pipeline, bringing the Hotspot app to all devices, including iPads. Naturally, the carriers probably have some control over how a subscriber can use that Hotspot app on their existing plans, but it seems pretty likely that all iPhone owners will be able to tether their devices to their 3G connection via WiFi soon enough.”
Phone companies do have ways of spotting people tethering, the easiest being massive spikes in data usage. But some Android users have had tethering built-in for a while (notably on the stock Nexus One), and I’ve yet to hear of anyone having problems.
What I’ve found using tethering occasionally on my Nexus One, though, is that it reduces the battery life massively: an hour of use, and it’s gone. By comparison, a dedicated device like the 3 MiFi 2 gives me several hours, easily.
Given that Apple focuses hard on battery life, and making sure that no app drains the battery too much, it will be interesting to see what its done to stop WiFi sharing killing your battery in record time.