The information comes from Twitter feed Eldar Murtazin (editor of Mobile Review). According to his information, production of the next iPhone (4G) has just started! The order would have been given by Apple to the manufacturer Tawanais Foxconn.
The next iPhone will be released in the summer of 2010.
Update December 11, 2009 at 10:40 am:
According to the same source, the iPhone 4G will indeed be finally multitasking. Even if we have not yet received confirmation that the design of the new iPhone will be changed, we can already be sure that the OS of the new iPhone will be massively reviewed!
We discuss it on the forum.