Yes. If you are an existing Verizon Wireless customer, you can redeem your New Every Two credit towards the purchase of an iPhone 4. You must be enrolled in the program and eligible for an upgrade. The iPhone 4 may not be available at some agent locations.
Verizon has announced that the New Every Two program will be ended on January 16, 2011. This means that existing customers who aren't already participating in the program can't sign up after this date. New Verizon customers will not be able to join the program, either.