I believe you can get a 90 day visa on entry but you can also go to the main immigrations office in Road Town and get a 60 day extension. As with any interaction with the BVI beaurocracy you can count on dedicating the better part of a day and possibly a second to the effort.

Travel is fatal to prejudice, bigotry, and narrow-mindedness, and many of our people need it sorely on these accounts. - Mark Twain