As reported earlier today, Apple has updated the App Store app, and with that update seems to come indication that the much coveted white iPhone 4 may be making its way to stores soon.
If you open the App Store app and navigate to the "Stores" area, then attempt to make a product reservation for an iPhone, you may note that there are black AND white versions listed. Unfortunately, if one attempts to reserve one of the white versions of the iPhone, you'll get the notice pictured. Attempting to reserve a black iPhone appears to work, though.
Still, this is promising indication that things may be changing soon, if you're one who has been holding out for one of these.