If you were wondering how I was doing push email tests on iPhone OS 2.0 and Vodafone UK, this is the reason why. The code wizard commandos at the iPhone Dev Team have been working on this non-stop since the early days of beta testing. In fact, I had iPhone OS 2.0 running on my iPhone since last week. That was version 5A345, two below 5A347, but identical in functionality.
The iphone-dev team says they are close to releasing an unlock for the iPhone 3G but are not there yet.
Link to Original Source