According to the announcement made on Friday during Apple’s special press conference to address the antenna issues of the iPhone 4, the company promised to give away free bumper cases to anyone who buys a new iPhone 4 and provide a refund for anyone who has already bought one. The company also stated that the offer will be valid through September.

Accordingly, the company has removed the bumper cases from its shore shelves and its online stores in order to prevent people from paying for an item that they are hereby entitled to obtain for free. Reports from readers such as Mike Polizzotto indicate that the online Apple Store has already marked the cases as out of stock and brought the price to $0.  In addition, retail stores such as Different District and iLounge are indicating an absence of the bumper cases from the retail stores.

While no specific details have been given out with regards to the refund mechanism or the distribution of free bumper cases, many industry watchers expect Apple to post instructions later this week.