If you purchase an iPhone 4 before September 30, 2010, you are eligible to receive an iPhone 4 Bumper or a select third-party case from Apple at no charge.

Follow these steps to apply for a Bumper or case.

1)Go to App Store and Search for "Case Bumper". You should be able to see the app.

2)Download and Launch the app on your iPhone 4 and sign in using your iTunes Store account or Apple ID.

3)Select your Bumper or case.

Visit here for more details.

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.