Today is the last day of Apple’s iPhone 4 Case Program, meaning that any potential iPhone 4 customer needs to purchase their phone today in order to be eligible for a free case. Notably, although the purchasing window is closing, customers still have up to 30 days from the purchase date to submit their claim. With the end of the Case Program, Apple is expected to put its Bumper Cases for iPhone 4 back on store shelves, according to a new report.…