How do I know you ask. a few key items from the iphone4 announcement.
1. video conferencing is wifi only till 2011.
Does this mean magically ATT will have a better network in january? or more like another carrier who can support high data rates?
2. Free upgrades to any ATT user whose contract expires in 2010.
This screams they are loosing exclusivity. What better way to make sure you dont have a landslide loss of customers, than to lock them into a 2 year contract right before you loose the only thing keeping them there.