Free Software Operating Systems for Old Laptops?

X-Nc asks: "I have an old 486 Laptop that does not have a CD drive and , if I remember right, a very small hard disk (a few megs), and maybe 4 megs of RAM. I would like to let my 6 year old son use this for him to play and learn on. What I'd -really- like to do is install Linux or one of the BSD's on it with enough apps to run a simple editor and a few other things. I have other systems that are able to run learning software and games. This would be for him to learn computer fundimentals. I remember in the old days that you could run X11 on this kind of system (my first Linux box was a 386DX-30 with 2meg RAM and a 20 meg HD). I have been digging around in some of the lists of distros to try and find something to load on the system but I can't seem to find one that's right. So, does anyone know of a Free Software (or even commercial) OS that can be installed on such a system that can do more than be just a terminal?"