What's my lag due to while playing video games?

I recently purchased a 32 inch LED Vizio TV, and hooked up my Xbox 360 via component cables. I put in Call of Duty: Modern Warfare 2 to try it out on the new TV but I'm experiencing an odd delay between my controls and the actions on-screen. The lag is somewhat minimal, being only about 1 third of a second off, but noticeable enough to the point where my gameplay is affected. What is this lag due to, and how can it be fixed? The TV is 60hz, but I also have a 47 inch Vizio at 60hz, without any problems.