Integrated Cleaning Sensors on Cameras

Hi Everyone !

So these days digital cameras are coming with self cleaning systems and the Nikon D80 does not have one? My questions to you guys are:

a) How does this effect the use and dust of my camera?
b) How do I clean the dust off?
c) How does it effect the cleanness of my camera and pictures?
d) How are you guys are coping with this advantage or disadvantage ?
e) Any other comments?

Thanks Guy !