The tutorial is fine actually, it only needs a VERY small bit of tweaking for it to work on Debian Etch:
1.Don't do the zlib install !
apt-get install libpam0g-dev openssl libcrypto++-dev libssl0.9.8 libssl-dev ssh zlib1g zlib1g-dev zlibc build-essential
3. then just follow the tutorial (the script is not actually important). But what falko forgot to mention, is that you need to copy the "script" contents to a file (e.g.: /home/chroot/chroot.sh) and then run that script:
chmod +x /home/chroot/chroot.sh
Then follow the rest of the tutorial.
Like I said, its just a question of updating your apt packages to etch level !