I don't know where you searched for pluto, but here is the official homepage.
From this page, there are some links to get pluto and the latest version is 188.8.131.52
Build a Pluto system for FREE!
To install Pluto on your own PC:
1. Download the latest kick-start CD:
MD5: 58fc3132aac06276b0343c13f7aef225 installation-cd.iso
FTP download: installation-cd.184.108.40.206.iso
2. Burn it using any CD burning software that can burn an .ISO image. Virtually all cd burning software does this.
Try that page, you will get Pluto from there.