US citizens traveling for business or tourism do not require a visa for stays of 60 days or less; however, proof of onward travel/departure, accomodation, and sufficient funds may be requested upon arrival. Your passport must be valid at the time of arrival and have at least 1 blank visa page.  There is a departure tax of around $30 so make sure to have some cash on hand when leaving Samoa. For recent changes in travel requirements and more detailed information, please visit the State Department website.