changing a file from mono to stereo

[Cheryl Homiak]

I had no problem with cds because they were sterio.
However, when making .wav files of mono casette tapes I used gramofile and
then oggenc. Then I
realized that the resulting ogg and wav files were, of course, still mono. I
thought maybe I could use the sox "split" option to convert such files, but
other than the mention of "split" in the manpages, couldn't figure out how to
use it.
can anybody tell me how to do this?
Thanks.