I did not fancy the idea of installing Cinelerra from source but fortunately someone is providing a repository.
All I had to do was edit my sources.list adding the following:
#deb http://archive.ubuntu.com/ubuntu breezy universe multiverse restricted
deb http://www.kiberpipa.org/~gandalf/ubuntu/breezy/mjpegtools ./
deb http://www.kiberpipa.org/~gandalf/ubuntu/breezy/cinelerra/i686/ ./
This first line was not necessary as I was already using the universe, multiverse etc.
Then: sudo apt-get install cinelerra