We've seen camera attachments for the iPhone before, including Griffin's noteworthy Clarifi case and an all but disposable plastic strap-on lens from another company; Digital King's offerings, developed by Japan's Toda Seiko, are a little different. They're designed specifically for the iPhone 3G rather than the iPhone 3GS, using an adhesive and magnetic attachment system to stick a magnetic ring to the back of your iPhone 3G, then attach and detach…