I just spoke to a Verizon spokesperson and got positive confirmation that existing customers will be able to upgrade to the BlackBerry Tour. They told me that there was a “minor glitch” in the system and they are working to let existing customers upgrade on the pre-order site by tomorrow (July 2nd).
They also confirmed that all customers will be able to purchase the phone on July 12th. So what are you waiting for? Keep refreshing your browser until tomorrow and let me know when it is available!