Sunscreen Labeling Protection Act of 2008 or the SUN Act - Requires the proposed rule issued by the Commissioner of Food and Drugs pertaining to over-the-counter sunscreen drug products to take effect 180 days after enactment of this Act, unless the Commissioner issues a final rule that includes formulation, labeling, and testing requirements for both ultraviolet B (UVB) and ultraviolet A (UVA) radiation protection before such time.