White models of Apple’s new iPhone 4 have continued to be more challenging to manufacture than we originally expected, and as a result they will not be available until later this year. The availability of the more popular iPhone 4 black models is not affected.

1. Download the iPhone 4 Case Program app from the App Store.
2. Launch the app on your iPhone 4 and sign in using your iTunes Store account or Apple ID.
3. Select your Bumper or case.

For iPhone 4 purchases made before July 23, 2010, you must apply no later than August 22, 2010; otherwise, you must apply within 30 days of your iPhone 4 purchase. To qualify for this program, you must purchase your iPhone 4 by September 30, 2010.

For existing customers who have already purchased an iPhone 4 bumper case, Apple also provides instructions. All credit card customers should already be seeing refunds, while those who paid with Cash, Check or Gift card at retail stores will need to bring their receipt back to the Apple Store.

Apple announced last week that they would be providing free bumper cases to all iPhone 4 customers and providing refunds for those who have already purchased them. The bumper cases help alleviate the signal loss issues experienced by some on the iPhone 4.

The email from Apple will look something like this: