Clicking noise IN Macbook...

the clicking noise has only gotten worse

If you sense that you may have a hardware problem, then you should probably take your machine in to have it looked at. It's very hard to diagnose odd noises without hearing them ourselves.

Does this same noise occur even when the machine is turned off? If so, it's caused by case parts rubbing against each other or against internal parts. Such noises have been reported here a number of times in unibody MBPs, usually involving the bottom pan of the computer. If your noise does occur when the machine is off, close it and turn it over. Press systematically on each square inch of the bottom pan, one square inch at a time, and see whether you can reproduce the sound. If you can, take the machine to a Genius Bar and demonstrate it. The remedy described by others who have reported such noises involves reducing friction between the inside of the bottom pan and a brace or support attached to the interior chassis (which I haven't seen, so I can't describe it any more precisely) by applying a small piece of plastic electrical tape to the inside of the pan where the contact occurs.

If your noise doesn't occur when the machine is off, I don't know what might be causing it, and I agree with Tuttle that you should head for a Genius Bar and let someone there diagnose it.

the exact same thing happens to me. i found out that since our macbooks have an accelerometer in them, it senses when the computer is moved so the head/pin reader on the hard drive does not scratch the disk. i dont think theres a way to make it stop but it protects your hard drive at least. hope I helped!