Study Objectives and Treatment Groups TODAYs primary objective is to compare the efficacy of three treatment arms on time to treatment failure based on glycemic control. Treatment failure is defined as: HbA1c >8% over a six-month period inability to wean from temporary insulin therapy due to metabolic decompensation. Secondary aims are to: compare and evaluate the safety and cost-effectiveness of the three treatment groups compare the treatments effects on the pathophysiology of type 2 diabetes evaluate the influence of individual and family behaviors on treatment response The three treatment groups are: Metformin (500-1000 mg bid) Metformin (500-1000 mg bid) plus rosiglitazone (4 mg bid) Metformin plus an intensive lifestyle intervention called the TODAY Lifestyle Program (TLP). This program is designed to promote healthy, moderate weight loss hrough changes in diet and increases in physical activity.