Like these guys said, bulk for a few weeks, then cut for a few weeks, and repeat as necessary. I used to 6 weeks bulk, 6 weeks cutting, and I went from 160lb to about 195lbs. It took a while tho.

For bulking, I did a lot of pyramid sets and tried to stick to the major movements on the free weights (squatting, dead lift, rowing, bench pressing, standing curls, military press). A lot of people reccomend shakes throughout the day, but some people, including myself, don't. Much like the "bad" carbs that RB listed^^, whey protein shakes normally don't last long. They break down quickly. I drank several glasses of milk per day, lots of eggs, chicken, ground beef (the leaner, the better) for protein. For carbs, I stuck with brown rice, whole grain bread (usually rye), and greens. And of course, tons of water, and plenty of rest. I usually ate 4x per day: breakfast, lunch, dinner, and a high protein before bed snack.

For cutting, I did high rep sets (10+ reps per set), and I did a lot of situps, preacher curls, arnold curls, overhead extensions, and butterflies with freeweights and I did spinning 3x week. The diet was similar, but I drank all water, no milk, egg whites with no yolks, boneless skinless chicken, and ground beef with no more than 10% fat. The carbs stayed the same, but less of it. 6 meals per day, breakfast being the biggest meal, and dinner being the smallest meal, and dinner was always at least 4 hrs before bedtime.