This might be an extremely stupid question, but for the life of me, I cannot figure out how to download this:
http://code.google.com/p/xmppframework/source/browse/#hg%25
hg is the executable for Mercurial, you're going to need to download and install Mercurial.
Once you have it installed you can use it to clone the project:
hg clone https://xmppframework.googlecode.com/hg/ xmppframework