Apple has been giving away free iPhone 4 cases since the problems surfaced about the antenna problems the some user were having. Now Apple says that the problem is solved for most of the units. Apple will soon end their free iPhone cases.
To get the iPhone case apple has the following requirement:
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.