The Office of Foreign Assets Control (OFAC) requires you check your customers’ names against the Specially Designated Nationals List (SDN List)—a “list of individuals and companies owned or controlled by, or acting for or on behalf of, targeted countries. It also lists individuals, groups, and entities, such as terrorists and narcotics traffickers designated under programs that are not country-specific.” 
Penalties for non-compliance: “The penalties for failing to comply with OFAC’s requirements are very, very harsh, indeed – including 30 years in jail, fines up to $10 million against corporations, $5 million against individuals and civil penalties of up to $1 million per incident.” 
Please note: This is not legal advice and dealers should always seek the assistance of qualified legal counsel.
From "19 Laws, Rules and Regulations That Can Cost You More Than Money" in the September 2010 issue of Auto Dealer Monthly.