RumorDog: New iPhone parts being ordered; iPhone Nano in the works?Aaron Baker - Editor-in-Chief
Additionally, rumor has it that Apple has ordered 100 million 8GB NAND chips, which is the main component for the device's internal memory. In regard to physical features, other rumors list the device as having a 3.2 megapixel camera, an FM transmitter, and video recording options.
Will Apple make a formal product announcement prior to launch? My guess is not - though they did this with the first iPhone, any sort of announcement would dramatically hurt sales of the iPhone 3G across all channels. With their entry into Best Buy and Walmart, I would venture to say that Apple wants iPhone 3G sales to be strong for as long as possible.
Sources: Digitimes & SlashGear