The iPhone Dev-Team has posted a video detailing what the iPhone 2.2.1 Firmware Update means for your device.
In summary, please don't update until a new version of PwnageTool is released that will create a custom ipsw of 2.2.1 which does not update the baseband.
In summary, please don't update until a new version of PwnageTool is released that will create a custom ipsw of 2.2.1 which does not update the baseband.