Patients with metastatic melanoma (melanoma whose tumor has spread) who have been treated unsuccessfully with gp100 vaccination may participate in this study. They will undergo apheresis or a tumor biopsy, or both, to collect lymphocytes. In apheresis, whole blood is drawn through a needle in the arm. A machine separates the blood components and removes the white cells. The rest of the blood is returned to the donor through a needle in the other arm. A biopsy is a surgical procedure to remove a small piece of tumor tissue.