My question is: Can I take the power steering components from my 81 F-100 and swap them to my 68 F-100? I would like to know if the steering column would also swap over.

 

The pump will work, if you have the right bracket (for the engine and pump), but the PS gearbox won't bolt up.
Neither will the steering column, although with enough time money and effort, anything can be made to work.

The parts interchange you are looking for is '65 - '79 - assuming we are talking 2x4 only. Ford made radical frame and other changes in '80 that reduce interchangeability quite a bit.

I used the PS system off a '76 390 in my '66 with a 352, but put on an '86 plastic bodied PS pump (which was introduced in '78).
Later I changed to a 460, and put on the late '80s serpentine belts pulleys and brackets system, but kept the '78 designed pump.

Good luck!