For genealogy researchers...

GenealogyBank.com has put a digital copy of the complete 1819-1820 U.S. Passenger List, free and online at: http://www.genealogybank.com/free. This is an exact digital copy of the original document that was published by the Federal Government and covers the arrivals in 35 ports in 14 states and the District of Columbia. You still have to pay to use all their features though!