DrogoNevets:
do you mean didtalWrite? even though its an analog input?
Analog inputs cannot function as interrupts. What exactly are you trying to accomplish here?
Are you looking for an interrupt to occur when a particular analog signal crosses a certain threshold? If so, you need to set up an external comparator as the source to a digital input that serves as your interrupt.
That, or code a 'software' interrupt that continually reads an Analog input and initiates some function when said threshold is crossed.
Or are you doing something else entirely?