[apalrd]

This is how common gamepads map to the FRC joystick data bundle:

Logitech DualAction:
All buttons labeled on the gamepad (including 11 and 12) are accessed as their button # - In LabVIEW, you can unbundle the Buttons and pick 11 or 12, in C++ you can do whatever you normally would do to get a button (I don't know exactly what that is)
Axis 1 -> Left X
Axis 2 -> Left Y
Axis 3 -> Right X
Axis 3 -> Right Y
Axis 5 -> D-Pad X (this is binary - +-1 is left/right)
Axis 6 -> D-Pad Y (binary also)

Logitech F310 or Xbox 360 is slightly different:
-Buttons 1-8 are used. They are not labeled, you can try reading all 8 and seeing what maps to what. I know that 9-12 are not used.
Axis 1 -> Left X
Axis 2 -> Left Y
Axis 3 -> Sum of L2 and R2 analog triggers - One is positive, the other is negative, both or neither is 0.
Axis 4 -> Right X
Axis 5 -> Right y
Axis 6 -> D-Pad X (binary like above - Note that you can't read D-Pad Y)

Any way you do it, a gamepad is a single joystick object.