What is the difference between megapixels on a DSLR Camera?

I'm looking at the Nikon D3100 DSLR Camera… And one store is selling a 14.2 Megapixel and another a 14.0 Megapixel.
Is there a big difference?

It's the same camera. One store just rounded down the number.

I agree. Don't put too much stock in the mp count on any camera - especially dslr cameras because the higher number is really more of a selling point than anything else.

Because I have two dslr cameras, one at 10mp and one at 15mp I can tell you that as viewed on a computer screen you can't tell the difference because the screen can only generate so many pixels anyway.