Share 'Google AdSense'

Does anyone know how much money can be made from Google AdSense? I know that major websites make a lot but what is possible with a small, low traffic website? If things take off with this site I am thinking of converting to a PAID network (no, you don't have to pay, as owner I have to pay) in which case the ADS you see in the right hand sidebar could help subsidize my cost of running this.