A couple more things... The roller_4.1_dev branch is pretty unstable at the moment with all the user management changes happening there. I'd recommend you stick with the trunk for now, or use the Roller 4.0 branch once it is created.
To retrieve the source you need a Subversion client. Once you've got it installed you can get the source like so: svn checkout http://svn.apache.org/viewvc/roller/trunk - Dave
