Gretel is now available from sourceforge.net. The CVS repository has been made available, and the distributable version has been built and posted in the File Release System.
A SourceForge project for Gretel has just been opened. The code isn't posted on SourceForge yet, but will be soon. Hopefully the code will be up next week (before 6 July). No promises, though. See http://www.cs.uoregon.edu/research/perpetual/Software/Gretel/index.html for the current version of the project.