The purpose of this study is to find out more information about the study drug iloprost for the treatment of symptomatic Raynaud's phenomenon (RP) attacks in people with scleroderma. A Raynaud's attack is defined as one where you notice at least one color change of your finger(s) (blue, white, or red) associated with at least one symptom (pain, numbness, tingling, and/or discomfort of the finger[s]). Your participation in this study will last approximately 9 weeks and will include 8 visits to the study center and 1 phone call from the study staff.