This study is testing the effect of etanercept in treating both the skin and joint symptoms of psoriatic arthritis patients. Enbrel®, also known as etanercept, has already been approved by the Federal Food Drug Administration for the treatment of psoriatic arthritis. It is taken as an injection under the skin. Participants in the trial will be offered etanercept free of charge to be self-injected once weekly for 24 weeks. During that period they will have 5 appointments at the study center and will also be asked to complete assessments of their health.

Individuals may be eligible to enroll in this study if they suffer from psoriasis (covering at least 10% of the body), and: - have had two or more swollen, tender or painful joints for at least 3 months or: - have lower back pain which your physician has diagnosed as sacroiliitis or spondylitis in one or more joints or: - have been diagnosed with active psoriatic arthritis