DIET.
Diet is a VERY important part of the mass-building equation. I would suggest writing down EVERY single thing that goes into your mouth for a week so you have an idea how much you need to be eating. You should eat a diet high in protein (at least 1g per pound of bodyweight) and high in calories (start with 15 x your bodyweight and increase 500 calories per week until your gaining weight at a rate of 1-2 lbs. per week). Chicken breasts, turkey, lean beef, potatoes, brown rice, and wheat bread are all good sources of low-fat, high-protein foods.
TRAINING.
I would recommend training each muscle group ONE time per week. Stick to basic compound movements that stress more than one muscle group, pullups, deadlifts, dips, and squats should all be staples in your training routine. Keep sets around 3-4 and reps around 6-8
REST.
I wouldnt recommend training more than 3-4x per week since your a beginner and be sure to get AT LEAST 7-8 hours sleep a night. Sleep is VERY VERY important in muscle growth and in increasing strength.
I wouldnt bother with supplements until you have your diet on track and are familiar with working out. A good multi-vitamin, creatine, and whey protein are good supplements to use when you start though. Also if you dont know how to do the exercises suggested you might want to go to Barnes and Noble or Borders and buy a copy of an encyclopedia of bodybuilding. Arnold has a good one out now, Gold's Gym has one, Joe Wider has a good one out too. Any of them will provide you with instructions on how to do the specific exercises.
Good luck!

