How could you remove dirt from the inside of a camera lens?

Michael and Allen are right. I'd like to add that the operation to remove the dirt from inside the lens element is likely to be far more expensive than the camera is worth or a new camera costs.

For what it's worth, that's something I've always left to professionals. Most cities have a certified local company that services cameras/lenses. Because lenses are usually expensive, have coatings on the elements, and have extremely precise requirements, I personally don't mess with them.

I wanted to answer this on three levels: 1. Like Jussi said, repair cost will be much more than replacement cost. Check out this ebay listing. Some are priced at $ 15. http://www.ebay.com/ctg/Pentax-Optio-S40-4-0-MP-Digital-Camera-Silver-/100059644. 2. On a positive note, you should probably be happy, you can see rest of the image, instead of getting annoyed with dirt marks :) 3. If you still want to clean it, it is a great opportunity to try it  yourself!  We have to first locate the dirt mark inside the lens.   Setup some reference scene with calibrations. See where the marks appear. Rotate the camera 90 degrees and compare the photos. Once the dirt is located, you could try to find out how it got in. If it could go in, you should be also able to get it out the same route. There are suction bulbs to clean out dust from DSLR mirrors. You might be able to use one of them to suck out the dirt. If you do break it apart, remember to take pictures and post them, it must be an interesting adventure! (Of course, you would need another camera. Of course, you are going to need another one anyway :)

I'm with almost everyone on this. Also there are cleaning kits you could get to clean it. Like the blower, lens fiber cloth. But if the dirt is appearing on your images, I'm sure it's inside the camera.  Once you've tried cleaning and the dirt is still there. Find a local repair shop.