hsv,

You are starting down a dangerous path!     Beware the Dark Side of flight simming.

If you are SURE that you are going to go this route, JUMP on getting that cockpit!  That is a HUGE move toward realism.  

The answers to your questions are not simple; there are TONS of options and possibilities.  Get a cup of coffee or tea and start surfing this forum section for likely topic headers.  There is a TON of info already here.

A very quickie type answer now..........

One option, ......and the cheapest...... is to get a USB joystick and "hack" it.  You remove the electronics from the case keeping the circuit board and the usb connection wire.  The multiple control axis are varied by what are called potentiometers that connect to the joystick physical controls.  Those potentiometers are variable resistors, ansd are sometimes also called "pots".  The amount of resistance they show to the electronic joystick circuit tells the sim where the control surface is currently set.

The challenge is to now develop a mechanical linkage of some sort to connect your controls to a set of new potentiometers that you beg/buy/steal that are of the same specifications (total resistance) as the originals from the joystick.  (You trpically can't re-use the original potentiometers.  They are usually tiny and physically weak.)  Most joysticks use 100K Ohm pots.  You check the old ones with a multimeter to be sure.

Once the physical linkage is connected, and the new pots are soldered to the locations of the OLD potentiometer leads (you can use some extension wiring), the joystick assignments will function based on what you set up in the sim itself.

There are MANY other ways to approach this basic task.

best,

......................john