A wiring drawing of what you had and changed for external connections might be helpful.
I did the experiment according to Figure 4-6 in the book "Getting Started with Arduino". It's almost the same as the website http://arduino.cc/en/Tutorial/Button showed except the board type and input pin. (Mine is pin 7). During the experiment the button seems not work because the LED was always off even when I press the button. So I changed the circuit several times including removing the button, connecting pin 7 directly next to source wire [ch65288]which turn on the LED). And all of sudden the problem comes out. And I realize the board was very hot then. :-/