[Luc1an]

well, you should be consuming about 1 to 1-1/2 grams of protein per every lb of body weight. you need protein to sustain muscle mass and strength etc. Im on about a 4000 cal diet with 250 to 300 grams of protein daily. About 70-80% of your protein should come from food, the other 20-30% you can substitute with protein shakes. Whey would be the most important protein you should take. Whey is basically milk by-product. There is two different kinds: Isolate and Concentrate(or blend). Isolate is about 90% protein per gram where as Concentrate is about 78%. Isolate is much more expensive tho but better bang for the buck. Ofcourse if your like me and take 6 or so scoops a day the concentrate works just fine. Before bed you should take Casein protein (1 scoop). Casein protein is a slow-release protein and should sustain your body and prevent it from going catabolic during the 8 or so hours of sleep where you body is receiving no amino acid intake. Casein protein takes about 7 hours to fully be processed by your body and prevents muscle breakdown. As far as "bulking up" or whatnot, protein alone will not make you do that.
As long as you maintain a lean diet your you will not put on needless fatty weight.

check out http://www.bodybuilding.com/ for product descriptions and reviews. Since you are not a serious body builder pretty much any whey or casein powder will suffice. let me know if ya need to know anything else.