Despite Apple warnings that magnets should not be used or attached to the iPhone 3G, USBfever is now offering both Wide Angle and Fisheye lens attachments for the iPhone. The lenses use a self-adhesive ring which surrounds the device’s camera to magnetically attach the lens body itself, making both easily detachable. The Magnetic/Detachable Wide Angle and Fisheye Lenses for iPhone are available now and sell for $17 and $20, respectively.…