And don't forget the basics -- protein and lots of it. Good quality stuff. Whey protein is generally considered best.
Try to take in about 1 gram of protein per pound of body weight each day. You can't absorb more than about 30-40 grams of protein at a time, so space protein out every 2-3 hours in the day. Be very sure to take in 30-40 grams of protein within 30 minutes of completing your weight training with simple carbs (like 100% fruit juice). Also, try to take in about 20grams of protein with some L-glutamine about an hour before bed -- gives your body something to build on and the l-glutamine will help reduce muscle catabolism over night.
You'll have a hard time putting on muscle mass without a good supply of high quality protein. I saw the results of my workouts, as they impacted my body, increase pretty dramatically once I cleaned up my diet and upped my protein intake.
At those levels, you'll go through a 5lbs tub of whey protein in about 2 weeks. It may seem expensive, but if you considered the equivalent in turkey or chicken, it's pretty affordable. And don't get all your protein from powder.