Seems like unlocking iPhone 3G would be a challenge since it have a new Baseband Bootloader. The tool that dev team showed was for the 1st gen iPhone to jailbreak and unlock.

So to the people that think the unlock for iPhone 3G is close, you might need to wait some more. Dev Team just manage to crack iBoot and this only open the ability to jailbreak iPhone 3G. No word yet about unlocking 3G phone.