I recently updated my iPhone (first-gen) to the new v2.0 firmware and it has been working smoothly so far.  I was able to successfully pair my Logitech HS01 Bluetooth headset (it's old, I know) to the phone.

However, for some reason, I can hear the other party through the headset but they cannot hear me talking.  I have tried to unpair and repair the headset to no avail.

I haven't yet tested this on another Bluetooth phone to see if it is defective (I wouldn't be surprised, after over 4 years of use, if something finally went wrong).  However, I wanted to see if anyone out there has had similar problems with Bluetooth headsets on the new iPhone firmware.  Are you finding that you don't have any problems?  Or are you in the same boat as me?