"Be aware that due to the way they operate, CMOS sensors are inherently "noisier" than CCD sensors, but if the individual pixel size can be increased by making the whole sensor larger or better layout on the sensor chip, then at a certain point, and with better mathematical fiddling, the CMOS chip can be made to be almost as good as an identically sized CCD chip. The advantages of the CMOS chip are easier manufacture, more logical elements can be installed on the same substrate (thus making possible one-chip cameras), and lower power consumption. For really critical low noise applications like astronomy then the CCD device will probably still be used.
CCD = Charge Coupled Device
CMOS = Complementary Metal Oxide Semiconductor, don't worry, it's just the description of the basic chip construction method."

http://homepages.tig.com.au/~parsog/photo/sensors1.html