http://www.vectorlinux.com Heres what I use on my ancient laptop. that one in my quote. If you want to here my success click on the link in my quote. It will take you to my blog on bringing this dinosaur back from fosillization. If you download VectorLinux make sure you download version 4.3.
Also try DamnSmallLinux at
http://www.damnsmalllinux.org I've heard that this will run on a 486DX /w 16MB RAM.
And yes the first paragraph is a helpful, yet cheap way to get people to check out my blog