Cleaning sensor on a Nikon D80?

So i noticed this little spec begin to appear on my camera. I took out the lens, cleaned both ends of the lens and the inside of the camera and it's still there. So unfortunately I think it has something to do with the sensor.
I want to know if this is easily fixable and what the costs of repairs could be.

Added (1). Also, what happens if there really is something wrong with the sensor and it isn't a spec of dust? Then what?

Here is a link that will tell you how to safely clean your sensor

http://www.kenrockwell.com/...t-2007.htm

My local Nikon service station and a local camera shop will do the cleaning for free. You might make a couple of calls in your area first.

Otherwise, it's an easy fix. Go to your manual and read page 125. There, you'll find the simple instructions for cleaning your sensor. I do it myself, when the need arises with a simple squeeze blower.

Here's a link to the manual, in case you've misplaced yours.
http://support.nikonusa.com/...hotography