More ATW800 related sites:
http://www.classiccmp.org/transputer/
Ram's excellent pages on transputers in general.
http://www.classiccmp.org/dunfield/atw800/index.htm
Dave's old computers ATW page. Has images of installation disks available for download.
http://www.michaelp.org/transputer
Extensive documentation can be found on this site.
http://www.acbm.com/atw/
Atari transputer user's mailing list.