"Fan" Noise from my Macbook Pro?

Hi!

Recently i have noticed a quiet noise from my Macbook Pro. It`s just a couple of months old, but I did not notice this in the start, when it was fresh new. It`s sounds like a low fan, and I can only hear it if it is really quiet. If I had noticed the from the beginning, I would not have been concerned, because it is so quiet. I had thought that I should be like that.

But now, I can not stop getting anoyed about it. Best hope is that here should be a quiet sound like this, and I can move one. But, if the Macbook Pro should be completely quiet, I need to visit the shop...

Anyone?

Kristian, Stavanger, Norway