Electronic Musican reviewed Cecilia this month, and give it quite a good review.
I just finished making my first MacOS X Installer for Cecilia. You need to have csound and Tcl/Tk already installed. Give it a try, report any issues to me.
Cecilia 2.0.5 has been released. There are a number of notable changes, the first being the first functional MacOS X port. Its seems to work well, but it still should be considered beta. This release also adds a number of new modules, fixes the help so it can be viewed now, and sets the helper app defaults to be modern programs.
Hans-Christoph Steiner just checked into CVS the first functional Mac OS X port of Cecilia. Look for a release soon after its properly tweaked.
Bill Beck at UC Davis' RE4M electronic and computer studio has released a Windows port of Cecilia, available here: http://music.ucdavis.edu/re4m/cecilia/ We are starting work to merge the two code bases.