1. Video switch boxes and cables. Be careful here as those boxes could cost as much as another monitor today.
2. About the color calibration. Such is done with the usual Pantone Huey or Spyder after the cables, boxes and more are setup.
I have a 27" imac and a pc side-by-side and would like to be able to hook up the pc monitor with the imac creating a dual monitor set-up keeping the ability to switch the pc monitor back to being the pc's dedicated monitor when not in use with the imac. What would be the best recommended hardware for doing this and also, when using the pc monitor with the imac, does that effect its calibration for colors? My purpose is to be able to do color work on the pc monitor when hooked up with the imac. Thank you in advance for your advice.