Sailboats based on Tahiti and Moorea will take you out for a spin, or even to the late Marlon Brando's island of Tetiaroa, but the best sailing here is among the Leeward Islands of Raiatea, Tahaa, Bora Bora, and Huahine. Having arrived here originally via yacht from the East Coast of the United States, I can say without qualification that the sailing among the Leeward Islands is world-class.
French Polynesia's center for charter-yacht sailing is Raiatea, where rentals are available from several companies (including The Moorings, the outstanding American company).
Raiatea shares a lagoon with Tahaa, its rugged sister island. Tahaa is indented with long bays sheltering numerous picturesque anchorages, and you can sail completely around it without leaving the lagoon.
If you are reasonably skilled at "blue water" offshore sailing, both Bora Bora and Huahine are just 32km (20 miles) away, albeit in opposite directions. Most of the charter-boat companies will let you leave the boat in either Huahine or Bora Bora, so you won't have to beat back to Raiatea after your week or so of knocking around the islands.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.