The Others are seen living in a nice neighborhood on the island and capture Jack, Sawyer, and Kate (Ep: 3x1, A Tale of Two Cities).
Their leader may be the mysterious Ben.
The Others keep Kate and Sawyer captive in cages outside. Jack is held in the Hydra. Jack gets the upper hand when he does spinal surgery on Ben and makes it possible for Sawyer and Kate to escape.
Later, Jack and Juliet escape.
Ben was originally a member of Dharma, but helped the Others to wipe out Dharma (Ep: 3x20, The Man Behind the Curtain).
Learn more about individual Others.