I've been messing around with the same idea as far as sounds.
I am/was... a musician, so i do have some recording equipment.
What i was thinking about doing was this:
Using the mic line out, record the entire ah films soundtrack onto either my tape deck, or digital eight track..
Then using the mic line in, from line out on the tape deck or 8-track, record the soundtrack as a wav file on the computer.
Then use a sound editor, like the windows sound recorder, to take the soundtrack, chop it up, and make mini sound files, and use them for each part of the film.
Then to make the music and "action sounds" work together, i would record the music soundtrack on 1 track of the 8 track, and the action sounds on another, mix them and re-record them on the computer..
I bought music match jukebox a couple of years back, but i'm sure there are millions of others, that let you record unlimited length tracks from your mic or line in..
or if you only have a tape deck:
play the actions track using one program, and the music track using another, and mix them with there volume controls, and record onto a tape.
then play the tape back through the comp. and record that as a wav file.
These are just ideas that i've come up with, not saying that they will work for you.