This study will evaluate the efficacy, tolerability, and effect on the quality of life of infliximab in adults with moderate-to-severe psoriasis who are resistant to etanercept after 12 weeks of treatment or have failed 24 weeks of treatment with etanercept. Infliximab will be administered as an intravenous infusion of 5 mg/kg at Baseline (Week 0), Visit 3 (Week 2), Visit 4 (Week 6), Visit 6 (Week 14), and Visit 8 (Week 22).