Another stick you may want to consider hacking is a T16000M ... 4 axes (2 of those are tied to its single hall-effect sensor, though), 16 buttons + 1 hat ... and programmable with TARGET.
It's certainly not as hacker-friendly as the Aviator, but ... worth considering at ~$30.00
As for wiring switches like the ones in your picture, you just solder a wire from the 2 contacts on the board to the 2 contacts on the switch (simplest option). If your switches have more than 2 contacts (such as a momentary toggle that can be pushed up or down from center, or a lighted pushbutton), you just have to make sure to connect the wires to the correct contacts.
For your type of switch or button, you'll want normally open contacts (so that a button press closes the circuit).
edit - wow, I apparently missed half the thread prior to posting that ... nevermind. :]
Edited by Feed (11/19/10 04:49 PM)