Apple has updated its Apple Store app for iOS, with v1.1 now available through iTunes, and it seems to have brought with it suggestions that the white iPhone 4 release is finally imminent. MacRumors forum member Bandolier spotted that reservation options for the white iPhone 16GB and 32GB models have been added to the updated app, alongside their black counterparts.
Unfortunately, actually tapping the reservation options doesn't yet allow you to reserve a white iPhone 4. Instead, you get a message saying "Because of high demand, we are not currently taking iPhone reservations."
The white iPhone 4 has been significantly delayed after its announcement alongside the black version, with Apple blaming manufacturing issues. You can download the Apple Store app for iOS here [iTunes link].