Despite the huge hype in the Jailbreak community, The iPhone-Dev team is working hard to deliver the 4.2.1 jailbreak which will be untethered in the final stages. The 3 Beta versions have already been tested and the latest version is set to be released shortly. This is the first time that the dev team decided to test the jailbreak publically.
The first iteration of the software disabled Bluetooth functionality and crashed apps. The second beta fixed the native app crashing, including Task Switcher, but did not re-enable Bluetooth. The third update, the latest one available now, fixes more bugs to address problems with FaceTime, Winterboard and embedded videos in iTunes.
Most of the people eager for an Unlock and Jailbreak should patiently wait for the final build to be released.
Source : DevTeam Blog