On the eve of the official release of the iPhone OS 3.0 and just a few days before the release of the iPhone 3G S, the iPhone Dev-Team has announced that they have unlocked the 3.0 OS and they will be demoing the method of how to use the new yellowsn0w carrier unlock tonight.

If we can trust the image above, which we do considering the Dev-Team’s previous record, users who upgrade to the iPhone OS 3.0 and new owners of the iPhone 3G S will be able to unlock their phones to let them operate on GSM carrier globally.

The new yellowsn0w carrier unlock is being kept under wraps for fear of Apple fixing the weakness that the Dev-Team has found that allows the device to be unlocked. This is also good news for any unlocked iPhone owners who lost their unlock when they mistakenly upgraded to the previous firmware.

The official release of the 3.0 firmware is tomorrow and the unlock will be released very shortly before that, so we’ll have to see how long yellowsn0w will stay functional before Apple puts the kybosh on it.