The best book, by far, on the MD-80 was written by the Northwest Airlines training department. That may not be what you are looking for, but it is an easy read and is the best reference you could get for MD-80 systems. Of course McDonnell Dougles themselves had books of wiring diagrams on all their makes and models which are really handy if you can find one for your particular make and model.
CBT courses are probably what you are after. You'd have to get the disks from someone but I'm sure they are around. As I just said on another thread, I would never pay for any of this information. Your airline should provide you with enough study material to be successful. The above is only for your personal reference library.
TP