Not quite sure what your question is but here's an explanation of the whole megapixel thing:

OK think of it this way, you could make a picture on a piece of paper simply by using colored pencils and drawing dots. The more dots you draw the more detailed your picture would be. No matter how many dots you drew, you could break the picture down into dots. All you need to know about each dot is what color it is and how hard you pressed the pencil.

Computers are as dumb as posts. They cannot draw a line or be in the least bit creative. However they are good at remembering a lot of stuff. So we teach them to remember information about each dot.

Being computer nerds we can't simply call them dots, that's not technical enough. So we call them "Picture Elements". Over time that has been abbreviated to simply "Pixel". Each pixel is one dot.

Now the more dots we have and the smaller the dots are in a given picture, the better the picture quality will appear to be. As cameras and computers got better, they remembered information about first thousands and then even millions of dots. But being nerds again we can't talk about millions, that's too simple, so we use the prefix "Mega" to mean millions. Therefore a one megapixel camera simply has an image made up of one million dots.

Entry level cameras these days tend to record 4 megapixels. Better cameras go up to 8 or even 10 megapixels. The Hasselblad H3D-39 can even record a massive 39 megapixels of data!

Now the more dots the better right? Well up to a point. After a while if we are going to print normal sized photos, we reach a point where the printer can't print that many dots and our eyes can't see that many dots, so going bigger is not necessarily better. Specifics vary but this generally happens around the 5 - 6 megapixel mark.

So why buy an 8 MP camera, it's a waste of time right? Not necessarily. For two main reasons:

1) More megapixels means bigger prints. Let's say you take that one killer photo that you love, wouldn't it be nice to blow it up to A3 or poster size?

2) Cropping. With an 8 MP camera, you can do a fairly savage crop on your image without losing too much quality.

So I hope this clears up a little of the mystery for you! All the best with your photography!