I've been tasked with setting up a computer for my VERY computer illiterate grandmother. All she needs is something that has a simple web browser, a simple email client, and the ability to look at and print pictures sent to her via email.

The computer I have is an old Pentium 3 that currently has windows 2000 installed. I would like to put something on it that is very easy to use and very hard to screw up. I've thought about ubuntu with a crippled user account, but that is still way too much os then she needs.

Is there a distro out there that is designed with this in mind?

I'd recommend Slackware if you're familiar with it. It's not user-friendly enough for Grandma to be able to screw up, but everything is there software-wise (would you need anything other than Firefox and Thunderbird. If multimedia is desired, then mplayer will have to be compiled from source, but if you know Slackware that's trivial. I would also add Webmin for remote administration and either Swaret or Slapt-Get for updates.

The more user-friendly distros (Ubuntu, Mandriva, Fedora, PCLinuxOS) might not work well with a Pentium III anyway. I've had issues with Ubuntu (lack of speed) and PCLinuxOS (instability & lock-ups) on machines of that type. YMMV.