Jeff Chang's real name is Su Yang, a 28 year old chinese 5-dan(kgs 9d)
He is currently studying in Europe.
Su Yang was one of the main teachers of Go'n'Game's China trip 2005 and has taught go for many years. He offers online lessons and offline game comments on KGS. You can contact him on his e-mail, email@example.com.
He's an awesome guy and a great teacher. :D
An Interview With JeffChang: http://gosensations.com/?id=2&server_id=1&new_id=1343