i'm merely a PPL student (even though i'll probably work myself up to an ATPL), but a good way to get used to FMC's (and a relatively cheap way) is to use microsoft flight simulator with some good add on planes .. there is gonna be a 737NG released from
http://www.precisionmanuals.com/PROD...ners/737NG.htm that, within limitations of FS, offers a fairly complete FMC that should get you going with the basics .. also there is
http://www.dreamfleet2000.com/737.html .. a simulation of a 737-400 that has a pretty good FMC, and then there is the wonderfull
http://www.wilcopub.com/767_MFS.htm .. which offers a simulation of the 767 .. with the FMC included in this add on i can use the Big Boeing FMC Guide by Bill Bulfer and program it pretty much according to the real one ..
i know flight simulator doesn't come close to the real feeling of flying, but these add ons do a pretty good job at simulating the FMC within the limits of Flight Simulator ..