Help with iMovie and Mpegs

Hi,

I'm trying to learn about using iMovie to
construct a movie that uses mpeg clips that
I've downloaded from the internet.

I purchase Quicktime Pro so I can export the mpegs
as a DV but of course there's the no audio
problem.

So I got bbDemux to split the file into
audio and video.

I need help from this point forward.
What's the "best" way to get that audio
file into a useable format so I can
import it into iMovie as the soundtrack?
iTunes doesn't want to do this little job for me
or I can't figure it out.


One more question: Is there any way to
get a WVM file into iMovie?

Thanks for your help.

John