As mentioned previously, GrowlMail is moving away from being developed and supported by The Growl Project. One of the Growl Developers, Rudy Richter, is going to be taking over GrowlMail on his own.
All future communication regarding GrowlMail should be directed at this google group:
http://groups.google.com/group/growlmail-discuss
GrowlMail can be downloaded from here:
http://code.google.com/p/growlmail/
GrowlMail is being developed here (and I believe cloned on google code, but I'm not sure):
https://github.com/rudyrichter/GrowlMail
If it were not for Rudy we would be retiring GrowlMail outright. However, hopefully this move will allow for GrowlMail to be released a lot quicker while allowing The Growl Project to focus on Growl.
Chris Forsythe
Growl Project Lead
Chris