iPhone developer and hacker Sam Bingner has released Subscriber Artificial Module (SAM) method which will allow you to officially activate your iPhone 4, 3GS and 3G without hacktivating, or using original SIM card.
The recently released PwnageTool / Redsn0w jailbreak tools for iOS 4.2.1 requires you to transfer iPad’s 3.2.2 baseband to your iPhone 3GS & 3G in order to unlock it using Ultrasn0w 1.2. This has resulted in poor battery performance as has been experienced by many users. Some users have also complained about their device becoming very hot when in use.