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.
Sherif Hashim, the guy who found the exploit to unlock 05.12.01 / 05.13.04 baseband on iPhones running iOS 4 is back with a video, which shows us how to activate iPhone 4, iPhone 3GS and iPhone 3G without the original SIM card. You can use any SIM card you like ! iPhone 4 users though will have to cut SIM to micro-SIM card size before using it.