In the wake of this week's surprise announcement from AT&T that it would allow VoIP services to use its 3G network, some had hoped that meant tethering for the iPhone was soon to become reality. Not so fast. AT&T says it is still fine-tuning its network.Personally, I don't know how or why some in the tech community equated AT&T's VoIP announcement with tethering, but they did.

Tethering allows smartphones to act as laptop dongles and provide broadband to a computer without the need for a separate wireless broadband modem. The iPhone itself supports tethering, but the network operator -- in this case AT&T -- needs to officially back the service. Earlier this year, AT&T Ralph de la Vega had said that tethering would be available by the end of 2009.

When prodded for an update, an AT&T spokesperson told the Wall Street Journal, "Whenever we offer new features, we want to offer the best possible customer experience. For tethering, we need to do some additional fine tuning to our systems and networks so that we do deliver a great experience."

You may recall that MMS service was just activated for the iPhone AT&T, years after the service was available to most modern phones.

The bottom line? No tethering for iPhone. At least, not yet.