The Calendar team will freeze all Calendar-related strings tomorrow night (2008-01-21) at 20:00 PST (2008-01-22 05:00 CET).
Localizers are encouraged to start working on their translation of the upcoming Lightning/Sunbird 0.8 release after the string freeze is in effect. Localizers should try to finish a first draft of their translation by February 7th, 2008 (you can still check in corrections afterwards).
We are currently planning to release our first release candidate of Lightning and Sunbird one day after this date (2008-02-08) and it would be good if localized builds of all languages would be available by then, to enable the different l10n communities to test the localization quality.
Please direct all questions to the mozilla.dev.l10n newsgroup, which you can also follow via Google Groups.