Step 1: Tools
solder (60/40 or 63/37... not the lead-free silver solder)
flux (this is more or less a must-have to get good connection to pcb traces)
30 AWG wrapping wire
wire wrap tool (Optional, but makes things easier)
wire stripper (A razorblade works well on wrapping wire, but check out my instructional on "precision wire stripper" to see the one I use in this tutorial.
A DIP microcontroller
A small tactile switch
Step 2: Locate and remove the screws
Step 3: Voiding the warranty
Step 4: Remove the bottom half
Step 5: Remove the board
Now that you have removed the pcb, store the top half in a safe place, where you won't lose any buttons. If they do fall out, putting them back is pretty easy. They all have unique shapes, and they can't be put in the wrong hole.