Though the bumper program is not being stopped altogether, Apple has nevertheless announced that it will be discontinuing it's free program of sending out bumpers to all iPhone 4 users from 30th September.
Apple on Friday issused a statement on their website, in the statement, Apple says,
We now know that the iPhone 4 antenna attenuation issue is even smaller than we originally thought. A small percentage of iPhone 4 users need a case, and we want to continue providing them a Bumper case for free. For everyone else, we are discontinuing the free case program on all iPhone 4s sold after September 30, 2010.
Right now, an app is used by those qualified for Apple's free bumper program, to file a request for a free bumper. For all new purchases made of the iPhone 4 after 30th September, the Iphone 4 Case App will be discontinued. The iPhone must be have been purchased after July 23, to request a free bumber from Apple via the app. However, if you will be purchasing a new iPhone 4 after 30th September, you just have to call Apple care and get a free bumper.
It seems like Apple has definitely agreed that users of its iconic product, the iPhone 4, do experience some issue with the antenna and should be given a free bumper, but now, they are not handing them out to just about anyone.
Via Apple