user1,password1
user2,password2
etc..

The script:

for userdetails in `cat /pathto//users.txt`
do
        user=`echo $userdetails | cut -f 1 -d ,`
        passwd=`echo $userdetails | cut -f 2 -d ,`
        echo "useradd -d /user1/kopen3 -p `mkpasswd $passwd` $user"
done

run the script and redirect the output to a file, e.g:

./createusers.sh > userscript.sh
chmod +x userscript.sh