Joe - you may find these pages from Wikipedia a useful starting point
http://en.wikipedia.org/wiki/Puppy Linux.
http://en.wikipedia.org/wiki/Damn_Small_Linux.
The wiki articles have links to the official web sites for each programme plus other related info.
I haven't used them, so don't know what the pros and cons might be or how easy or difficult to configure, but they are free and they are small. I assume that once installed you will have the option of downloading and adding extra software to improve usefulness.

Quack!
GtD.