"Under certain conditions the new ultracompact Apple USB power adapter's metal prongs can break off and remain in a power outlet, creating a risk of electric shock. Users with ultracompact power adapters should immediately stop using them until they exchange them for a new, redesigned ultracompact adapter."In the meantime, users should charge their phones via the USB cable only. Replacements can be ordered at this web address, or at your local Apple Store starting on October 10th. Hit the link for the full details [Apple]
Apple has revealed that the tiny little USB power adapters that shipped with the iPhone 3G are potentially dangerous and must be recalled.