Hello All -
Found a great site about the archives at The Mitchell Library in Glasgow. There are six parts of this video. It is very informative about the various sources available at the library. If you get a chance go to see their archives in Glasgow. The Mitchell Library is probably the best archive for the Western area of Scotland apart from Edinburgh's archives.
The link to view these videos is listed here: http://www.scotlandontv.tv/scotland_on_tv/discover/Mitchell_Library_Scottish_Family_Research.html