USB Fever has released two new products for the iPhone 4.

The Retro Cassette Tape Case for iPhone 4G (http://www.usbfever.com/index_eproduct_view.php?products_id=2035) is an US$39.99 case for the Apple smartphone that looks like a cassette from yesteryear. The Aluminum (Metal) Back Cover for iPhone 4G (http://www.usbfever.com/index_eproduct_view.php?products_id=2038) is a $12.99 case made of aluminum and filled with a neoprene lining.