A developer / hacker responding to the name of Tarek Mansour has successfully activated the FaceTime video conferencing feature on his iPhone 3GS jailbreak recently.
To achieve this, he has developed a “FaceIt-3GS” mod which he will make available soon on Cydia.
Currently, the camera is not supported (it indicates to work there) but the audio transmission passes perfectly!
However, you will have to use a mirror and show skill in using video conferencing;)
We discuss it on the forum.
FaceIT 3GS from iPhoneIslam on Vimeo.