How to use a resistor ladder?

Hello, I'm pretty new to Arduino. I was looking at an electronics website and saw a 4-button keypad with five pins: ground, and one for each of the buttons. I'd like to know how I could read the button states using only one analog pin, assuming that only one button will be pressed at a time. How would I do this with a resistor ladder? I've thought about connecting these pins:
Keypad GND to Arduino 5V
Keypad pin 1 to 10k resistor to pin 2 to 10k resistor to pin 3 to resistor to pin 4 to resistor to pin 5 to resistor to Analog Pin 5. (Sorry, a bit redundant.)
How would I read the input values with analogRead()? I'm not great at calculating this kind of stuff.

Thanks,
charredgrass

http://forum.arduino.cc/index.php/topic,8558.0.html