I've compiled a collection of as many old versions as I could find if anyone is interested. This includes several versions not listed on the homepage, and the documentation associated with each revision.
The individual versions can be found here:
http://www.y-less.com/uploads/PAWN/For each 3+ version I could find there is a separate download, plus "misc.rar", which contains two versions prior to 3.0, as well as a couple of other projects and files that haven't changed much over the years (at least as far as I looked in to it).
The whole lot together can be found here (85 Mb file):
http://www.y-less.com/uploads/PAWN.rarThis was mainly done as SA:MP still uses a hybrid of 3.0.3367 (VM) and modified 3.2.3664 (compiler) and someone wanted the documentation from those versions. I just went a little further.