How to use interpput in fez spider?
Do you mean an interrupt pin?
@ Weiti - no i know pin 3 is interrupt pin. bt how to use ? please send me source code
pin 3 is interrupt?
now I have to ask more questions 
What do you want to do?
Do you want to get an event thrown on the state change of a pin?
@ Weiti - yes
this is not an off topic discussion. please move to correct forum.
your question is. too vague to answer.
Check out this codeshare by ertonmayor
It should explain anything you need to know about using an interrupt port.
http://www.tinyclr.com/codeshare/entry/397