Here’s how it works:
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.
You can apply for a bumper (the only available color is black) or any other qualified case, all of which are free if you’re eligible. It’s a 3-5 week wait for delivery, because nothing in life is quite as easy as it should be. [Apple]