Hello NHL411!
Creatine is a naturally occuring substance in the human body. It influences muscular contraction, allowing the user to slightly increase strength. The intention is to take it while eating higher calories (have to eat to grow, hehe) and get better gains over time. I have used it first hand and seen results with it. As it has gotten much cheaper in the last few years I would recommend it if you are serious about lifting and gaining mass.
I would recommend creatine if it is used in cycles. It is not dangerous to the body, it just loses potency as your body gets used to it.
The first few days of using creatine it helps to take a good amount (called creatine loading, most creatine products discuss this in thier directions). I then cycle creatine for 2-3 weeks using the recommended amount on the directions.
After you have eaten like a madman and used creatine you should put on some muscle mass. I usually do more cardio for a 2 week period to shed any bodyfat accumulated during the heavy eating and show off the new mass. This two week period allows my body to lose its"tolerance" of creatine so it has a better effect during the next cycle.
You can repeat this system to put on weight and stay cut up year round.
Hope that helps.