On the back of the iPhone there's an increasing number of large and small icons and numbers. What do they mean?
This Ars Technica article runs down the long list of symbols and numbers. It's interesting reading.
This only covers the iPhone that is authorized to operate in the US, Canada, and Europe. iPhones manufactured for distribution in other countries may have a completely different set of certifications printed on them (some devices, like the Kindle, slap every regulatory stamp they get on the back so they have one version that can ship anywhere). All the rest of the iPhone's compliance medals that we didn't discuss here can be viewed in the device's Settings menu (General > About > Regulatory), along with the names of the countries that use them.