the javascript files that make up the basis of the mushpup system are now available at Google Project Hosting:

http://code.google.com/p/mushpup/

Google Hosting offers a Subversion repository system.  More information on Subversion can be found here:

[[http://subversion.tigris.org/ Subversion Home Page]]
[[http://en.wikipedia.org/wiki/Svn Wikipedia Entry]]
[[http://svnbook.red-bean.com/en/1.1/index.html Version Control with Subversion (online book)]]