This is taken right from a BVI Official Web Site:

All visitors who are non-British Virgin Islanders who wish to enter the Territory should note the following:

i. Visitors must show a valid passport on entering the BVI.

ii. US and Canadian citizens may also be granted entry using an authenticated birth or citizenship certificated and a current picture identification.

iii. Bona fide visitors may be granted entry for up to one month at the ports of entry, provided that they posses return (ongoing) tickets, evidence of adequate means of support and pre-arranged accommodation during their stay.

iv. Visitors who wish to extend their stay should apply for an extension from the Department of Immigration in Road Town, Tortola or at the Government Administration Building in Virgin Gorda.

v. Visitors from certain countries may require a visa for entry. If in doubt about the necessity of a visa, contact the nearest BVI Tourist Board Office, the nearest British Embassy, or contact the Chief Immigration Department, BVI Government at Tel: (284) 494-3471 or 494-3701 ext. 2538.

Please note
According to the BVI Immigration and Passport Order, 1980, the classes of persons commonly known as Rastafarians, and as hippies are prohibited from entry into the Territory. However, persons within these classes may seek special approval from the Chief Minister's Office by writing in advance to:

Permanent Secretary, Chief Minister's Office,
Road Town, Tortola,
British Virgin Islands.

Fax: (284) 494-6413.