If this rumor is true, the new iPhone would be a more of a revolution and not just an upgrade. According to PhoneNews (via IntoMobile) Apple is having its retailers clear out the Apple Composite AV Cable and Apple Component AV Cable as it is supposed to be replaced by a new Apple AV Cable that supports both.
This new cable would allow you to connect the new iPhone 2009 and future iPod touch devices to HDTV and standard resolution TVs. PhoneNews goes even further saying that the new iPhone 2009 (they call it iPhone HD) would have a higher screen resolution supporting 720p HD video playback.

The new HD video support of the iPhone would allow you to watch videos stored on your iPhone on your big screen TV, but also like the Apple TV stream video via iTunes.
If all this is true the new iPhone 2009 would be an Apple TV in your pocket usable at home and on the go for watching vidoes in HD quality.
Technically there is no high barrier to offer this capabilities. Putting the individual feature together the Apple way would trigger yet another media usage revolution.
More iPhone 2009 News and Rumors.