An informative article by Rajiv Makhni busting the myth of megapixels in a digital cameras.
Even the size of each pixel matter, here the big boys- DSLRs score much better. Because of the larger sensor size, the pixel size is also big as compared to a smartphone cameras.
Bigger pixel = Better picture
Highlighting megapixels is more of a marketing gimmick by the camera phone industry, the quality of the image depends on many other factors as mentioned in the article