this reminds me of a tool called "keepit" (http://www.keep-it.com/) which was the exact kind of thing you were after. It was perfect for one man shows, but sadly it is no longer developed and doesn't run properly in XP SP2. I had to turn to tortoiseSVN which is total overkill. I'll have a go with yours and give you my feedback
In what way doen't it work in XP. I found that it indeed won't install properly. It put's two dll's and an inf file in the folder: C:\WINDOWS\system32\ShellExt
The dll's won't register on install, but if you register them manually keep-it seems to work ok.
BTW: are you aware of VCS lite: http://www.acaciacons.com.au/vcslite/vcslite.htm
It also let's you keep revision of files in a compressed archive.