The iPhone 4 free case/bumper program has now opened in the UK.

An email has been sent to each and every registered iPhone 4 owner with instructions on how to either, a) order a free bumper or case, or b) claim a refund.

To order a case, you must download the same iPhone 4 Case Program app that was available to US customers at the tail end of last week. Once opened, you sign in to your iTunes account and are offered a variety of cases, and the black version of Apple's official bumper.

Unfortunately, the coloured bumpers, for those who want to dress up their iPhone as a 1980's legwarmer, don't seem to be available on the free giveaway, but there's still a healthy variety of cases, including those from Incase, Belkin and Griffin.

You will have to wait a while, though. The earliest any of the cases will ship is 3-5 weeks, with some of them even listing 6-8 weeks for delivery.

The refund process is slightly more complicated, with different options based on factors, such as where and how you bought the case or bumper.

Credit/Debit Card purchases will already have been refunded, claims Apple. For cash, cheque, or gift card purchases at an Apple Retail Store, you will have to return to the store with a valid receipt.

Those who used cheques or wire transfers to Apple online will be contacted by the company and asked to provide bank details for the refund. Be wary though, Pocket-lint could see a spam scam emerging, so do check (by phone) that this is authentic before handing over any details.

Finally, if you bought a bumper from O2, you will have to fill out an online rebate form.

Phew!

Do note though, you don't have much time to apply if you bought your iPhone 4 on or before July 23. The deadline in this instance is August 22 2010, presumably because it will take Apple a few weeks to deliver. Otherwise you have to apply in the 30 days after you bought the device.

The offer is open to anybody who buys an iPhone 4 up until September 30.

Good luck!

Check out our feature on Free iPhone 4 cases: What to go for?