The LTSP is currently known to work on Redhat, Mandrake, Suse and Debian.
I have received a report from David Anders (dave123@abcsinc.com) who was able to install LTSP on SCO OpenServer 5.0.5!
At some point, we would like to include the instructions for the other distributions, so if you have had some experience making LTSP work on platforms other than Redhat, please send us some info.