This is very important.

A typical phone has a 1/8" sensor. The iPhone 4S has a 1/3.2" sensor, which captures 6 times more light.

The N8 has a 1/1.9" sensor, so it captures almost 3 as much light as a 4S. 1/2" sensors are standard for point and shoot cameras, so differences in quality between point and shoots and the N8 would be mostly attributable to the optics of the respective cameras.

The 808 has a 1/1.2" sensor, so it captures 2.5 times as much light as the N8.

If you're keeping track, that's 44 times better than a typical camera phone.

This size is comparable to the worst compact DSLR's (the four-thirds system used by Olympus and Panasonic), although even cheap DSLR's are likely to have much better optics than a camera.