All of this has been covered before, over and over and over.
If you want to use Slackware 12's stock compiz package, and nothing more:
http://slackwiki.org/Compiz
If you want Beryl or Compiz-Fusion:
http://www.linuxquestions.org/questi...ack-12-575521/
which ends up pointing toward some well made scripts to download/install everything.
