This study will examine the safety and effectiveness of a monoclonal antibody called humanized anti-Tac (HAT, also called daclizumab) to treat children and adolescents with uveitis (chronic inflammatory eye disease) associated with juvenile idiopathic arthritis (JIA). Monoclonal antibodies are genetically engineered proteins made in large quantities and directed against a specific target in the body. The HAT antibody is designed to prevent a specific chemical interaction needed for immune cells to produce inflammation. Current treatments for uveitis include steroids and immune-suppressing drugs. These treatments do not always work or they may cause significant side effects. This study will determine whether daclizumab can improve uveitis in children and reduce the need for other medicines.