2. Let's go
1.1. Who is Marillat
I don't know who is Marillat, if he is a Debian developer or whatelse. I only know he has a french email but more important he has been packaging a lot of very usefull tools not already present in the Debian distribution.
This howto briefly describes how to install the packages provided by him.
2.1. Updating /etc/apt/sources.list
In order to get Marillat's packages you have to add the following line in your /etc/apt/sources.list:
deb http://www.debian-multimedia.org etch main
2.2. Importing Marillat's key
In order to guaranty the packages have really been created by Marillat, import his key:
gpg --keyserver pgp.mit.edu --recv-keys 1F41B907
gpg --armor --export 1F41B907 > /tmp/key.asc
apt-key add /tmp/key.asc
2.3. Installing Marillat's packages
Update your repository list
and install one of the Marillat packages
apt-get install package_xxxx
Of course, you can use synaptic which is much more easy to use.