Most of them appear to be legal for download. I own the McCurtain CD's for everything Cessna 150 related, and many of the OEM Cessna CD's and microfiche on other models. I have compared these to sample pages from the micro-tools website. While most individual pages I checked obviously were not either Cessna's or McCurtain's work (the presence of owner's notes, greasy fingerprints, etc.), there are a few that did come from the McCurtain CD's as identified on certain pages (the webpage owner may or may not be aware of this). The manuals themselves and the material within cannot now be copyrighted by anyone, as all of the material listed is now public domain. The offering of McCurtain's work in scanning certain manuals is questionable at best, and is probably illegal, but the material itself is legally available elsewhere! (Sorry, I didn't take notes on which manuals are McCurtain's copies.)
There are errors in the listings. The pre-1963 service manual does not contain any cessna 152 specific information, for instance, and the 1969 Cessna 150 service manual is actually the 1969-1976 Cessna 150 service manual. There are other errors, I'm sure. It should also be noted that while most of these manuals have not had updates issued by Cessna in decades, there is no guarantee that ANY updates were incorporated correctly prior to scanning.
You will notice that this particular webpage cannot be accessed directly from any link on the Micro-Tools website, and may be an unprotected page not intended for general public access. BTW, you didn't check your link, Kirk! The extra comma needs to be deleted for the link to work.
http://www.micro-tools.com/pdf/Cessna/ 
