I just wanted to remind everyone that as of last night, Wednesday, September 9 at 23:59 PST, the firm string freeze went into effect. That means that all strings are now entirely frozen until we release Thunderbird 3 beta4.
We are planning to accept localizations up until Monday night next week pacific time (September 14 23:59 PST). So please opt-in for the beta 4 release until then. You can opt-in in the corresponding opt-in thread in the mozilla.dev.l10n newsgroup.