The purpose of this study is to achieve approval for the use of carbidopa/levodopa/entacapone in early Parkinson's disease (PD) by demonstrating that when used as initial levodopa therapy in early PD, carbidopa/levodopa/entacapone provides significantly greater symptomatic benefit than immediate release carbidopa/levodopa administered at the same levodopa dosage level 100 mg t.i.d.