Most of my codes are now available on the Google Code website. A simple way to download the codes is with the svn system. SVN is, as Wikipedia puts it:
A manual is available online here: http://svnbook.red-bean.com/en/1.5/
So, basically, you just need a SVN client to download a code. There's a bunch over there: http://subversion.tigris.org/links.html#clients
For Mac I use svnX. But this is just a GUI, so you need a working install of Subversion. Check here for a nice and easy way to install Mac package.