Since Engadget and many other sites including Dev team blog were speculating that if you jailbreak your iPhone 3G with 3.0 software you might break your YouTube application, we can now confirm that this won't happen.
We've seen iPhone 3G that was jailbroken with a new windows version of Redsn0w application and that every single feature including YouTube was working just fine. We have to wait for the Ultrasn0w application to be able to make any calls, but since this application was promised for last Friday, we expect to see it any day now.
Many sites including modmyi.com are reporting that iPhone 2G can be jailbroken and unlocked while you have to wait a bit more for 3G unlock. So far, there are no reports on any jailbreak / unlocking success for the new iPhone 3G S.