Serpent,
Creatine is naturally in your body and is a much needed part of the energy system of the muscle. ATP is the immediate energy source for activities like sprinting and weight training. Thus a small amount of ATP is stored in skeletal muscle. When that ATP is used, it breaks down into ADP. This ADP then interects with creatine phosphate to create more ATP. This means creatine supplementation will add to the existing creatine in the muscle and allow you to work a bit harder. Harder work = more adaption = more gains. After this ADP-CP resevoir runs dry, your body then metabolizes sugar (glucose/glycogen) in the muscle for energy. The waste product of this conversion is lactic acid... There is a good amount of creatine in red meat, so it is a naturally occuring product; much like protein.
Guys,
I've had decent results with Cell-Tech in weight gaining, but I believe that's because of the 30-40g of carbs it has in every serving as well. This helps with the afore mentioned insulin spike. Any consumption of a good amount of simple carbs will cause an insulin spike.