Just got my 3GS in the mail today - sweet. I had already upgraded my 3G to 3.0, and enabled tethering, which works perfectly over Bluetooth and USB connected to my early 2008 Macbook (which doesn't need recent Bluetooth 2.0 update from Apple). Here's what's happening with the 3GS over Bluetooth: 1. Pair over bluetooth, with tethering set to 'On'. 2. Initiate connection from Macbook bluetooth menu > select 'Connect to Network'. 3. Connection works for ~2 seconds then drops. 4. I deleted Network Profile 'Bluetooth PAN', 'forgot' Macbook bluetooth connection from iPhone, 'forgot' iPhone bluetooth connection from Macbook, restarted both, rinsed, and repeated FIVE times. Same symptoms every time! ...so... let's try this over USB... 1. Plug in iPhone. 2. Popup for New Network Connection appears, confirm and hit 'Apply' in Network sysprefs tab. 3. Nothing happens. Check iPhone for blue 'tethering status window', nothing is there. Check iTunes, shows iPhone as connected to computer. 4. Check in Settings>General>Network AND TETHERING OPTION HAS DISAPPEARED. 5. Reinstall Carrier Settings to enable tethering, restart iPhone and Macbook, and repeat. SAME THING HAPPENS. Help? Is there a killswitch being executed by iTunes that resets this until ATT approves tethering? Why is this only happening on 3GS? Thanks for your help. I searched and searched and haven't seen this problem yet. Edit: See post #10, some solutions are now available, but just workarounds.