I put together a package which includes the Admin console translation, the French date zimlet, the French spelling and the Web client translation.
It also includes the 'install.sh' script that installs all this. The script must be run as root with Zimbra 4.0.4 already running.
The same package can be found at http://files.whitehatmail.fr/ (enter with user 'invite' password 'invite') in the Zimbra directory. It is too big to upload it to the forum (300KB, limit is 145KB). The file name is zcs-fr-4.0.4_GA_406.tgz.