Getting compiz running on squeeze is surprising easy. Debian has included a document to help set it up, but there are a few little things necessary to get it to be usable.
1. Get the packages installed.
apt-get install compiz compizconfig-settings-manager compiz-fusion-plugins-main
2.Follow the instructions here: http://wiki.debian.org/Compiz to customize your /etc/X11/xorg.conf file
3. restart gdm
/etc/init.d/gdm restart
4. open up a [...]
Compiz desktop in Debian Squeeze