Caution from UTF-8 Contrib:
If you have extra tables that contain text in English or UTF encoding from Moodle 1.5, and you want to convert them manually to be used under 1.6, ... (Please make a backup first)This script assumes that your table prefix is mdl_, if it isn't, edit the script accordingly. On a *nix machine you can run this command:
mysql --password='somepassword' moodledb < /pathtoscript/quickmail_en_to_utf8.sql > /pathtoscript/quickmail_en_to_utf8.tab