OP, which tutorial did you read? Please provide a link.
digimike provided a typical starting point for keypads but that keypad needs no resistors IIRC. Did a search for resistor and found none. If you use internal pull up resistors you don't need resistors.
I have a library of my own, except it's not limited to keypads. It's capable of virtually any input hardware with the same interface calls so you don't have to learn a new library for every new hardware. If you have time, check it out.http://liudr.wordpress.com/libraries/phi_interfaces/