Help with simple loop screens

I have a bunch of files that begin with "man", which is then followed by numbers and possibly underscores. I need to make copies of all the files that begin with "woman" instead.

I know this can be done with a simple for loop, but I can't get it working.

Thanks for any help,
gm

#!/bin/sh
for file in `ls man*`
do
[ -f wo$file ] && echo wo$file exists && continue
cp $file wo$file
done

Thanks very much.