To use the greylite debian repository:

Become root, open /etc/apt/sources.list and add the line:
deb http://mij.oltrelinux.com/net/greylite/packages/debian sid main contrib non-free

Save, exit, give (as root) the commands
apt-get update
apt-get install greylite

and answer "y" when asked for the security question.

Enjoy!