phpwcms uses Google Code for development:
There you can find the public SVN repository.
Some users publish custom install packages based on latest revisions:
I recommend the following SVN clients for general users:
Windows - RapidSVN http://rapidsvn.tigris.org/
Mac - ZigVersion http://zigversion.com/
All others might be happy with Command line clients (I hate).
I use TortoiseSVN on Windows and ZigVersion (or...) on Mac.
You can browse all changes:
This is unsupported but should work and is stable (wait 1-2 days after a new revision is avaialble to be on the safe side).