It is needed to convert the change in resistance of the sensor into a change in voltage that can be measured.
The analogue input can only measure voltages not resistances.
Sorry for the late reply. I was doing some research on it, and I just understood the concept of a pull up, pull down resistor. So basically my setup should be like a pull up resistor, having the LDR as a switch. one end of the LDR and the Resistor should be connected to the analog Pin. Is this rite?
(Btwn.. thnx for the link... Its really usefull)