Although not technically Apple's fault, the death of a Chinese flight attendant (who had purportedly been electrocuted by a third-party iPhone charger) has prompted Cupertino to create a site meant to help consumers recognize 100 percent genuine, actual Apple-approved chargers.
The page only exists on their Chinese-language site, but thanks to a little help from Google Translate, us English speakers, too, can benefit from its infinite wisdom:
Apple always put the user's safety first, so all of our products are subject to stringent safety and reliability testing, and designed to meet government safety standards around the world, including for the iPhone and iPad USB power adapter.
This overview will help you identify genuine Apple USB power adapter. When you need to charge the iPhone or iPad, we recommend that you use the supplied standard USB power adapter and USB cable. These adapters and cables are also available separately from Apple and Apple Authorized Resellers.
Of course, most of the third-party chargers you buy will probably come from perfectly respectable manufacturers and give you no problems whatsoever. But just in case you're worried that you might be stuffing your socket with a counterfeit, this should put your mind at ease. [9to5 Mac]