So to use pin 0 as a switch input you should just be able to wire the switch from ground to the input pin. When switch is pushed your digitalRead() will return a zero and a one when not pushed. Try it and see if that doesn't work better for you.
You can wire all your switches this way. For the other pins (besides 0 and 1), turn on the pullup resistor, using digitalWrite(pin, HIGH).
This lets you write code that doesn't matter which pin the switch is attached to.