Up to 132 participants will be enrolled. There will be a physical examination and collection of blood samples for tests, and making sure that x-rays and scans are current. Patients will be randomly assigned to four groups. Group 1 will receive the peptide with an adjuvant (assistant) oil-based liquid called Montanide ISA-51, as an injection in the thigh. Group 2 will receive gp100, Montanide, and a cream called imiquimod, which the FDA has approved for treating genital warts and herpes but that may help immune cells in the skin to recognize the vaccine. Imiquimod will be applied to the skin for 5 days. Group 3 will receive gp100 mixed in salt water given as several mini-doses under the skin of the thigh. Group 4 will also receive several mini-doses of gp100 mixed in saline, as well as imiquimod cream applied to the skin for 5 days. All patients will receive the gp100 every 3 weeks for 12 weeks. Every dose is a cycle, with four cycles considered a course of therapy. If the melanoma does not return or patients do not experience side effects from this therapy, then the courses of vaccine will repeated for up to 12 cycles of therapy (3 courses over 33 weeks). Side effects of the peptide vaccination include local swelling, swelling of local lymph nodes, bruising, and pain and redness at the injection sites. There may be chills or fever. Patients will be watched closely for such side effects.