How-to: Enable tethering under iPhone 3.0 right now (Updated)

Update: This hack has been found to disable Visual Voicemail for AT&T customers in the U.S. and is no longer recommended. If you performed it you can re-enable VVM by following these instructions.

9to5Mac has posted a killer tip on how to enable tethering right now on your iPhone running the brand-spanking-new 3.0 software. It only takes about 60 seconds.

Simply download and mount a carrier settings file for AT&T* (from Gizmodo), then option-click on Restore in iTunes and restore your iPhone from the mounted disk image. You'll see a message that says "Updating iPhone carrier settings..."

When complete, go to Settings > General > Network and you'll see the new setting for Internet Tethering magically appear. Tap on it, slide Internet Tethering to On and you're in business.

*If you're on another carrier, try this file. Carrier settings for Fido in Canada and O2 in the UK can be found here.

Update: This hack has been found to disable Visual Voicemail for AT&T customers in the U.S. and is no longer recommended. If you performed it you can re-enable VVM by following these instructions.