One or two things didn't work straight out of the box for me, so this what I had to do (as root):
apt-get install fvwm
apt-get install fvwm-icons
ln -s /usr/X11R6/include/X11/pixmaps /usr/include/X11
This is my .fvwm2rc file. This is more for me when setting up my desktop on a new machine than for anything else. It's just simple and functional.