I think that's normal with the MacBook Pro's when the CPU is very active. Remember, they are, relatively, very slim (and, therefore, quite dense) laptops.
I have seen reports of them getting quite warm but I think, unfortunately, that's by design. I know with my once I step in the CPU or GPU a bit the fans spin up and it begins to sound like a business jet (I like jets, though), but I could see how that may annoy some. However, its way better than the Sony I tried whose fan STAYED ON and always sounded loud.