An AppleScript which allows arbitrary tagging of messages in Mail.app. Select any number of messages in Mail.app, and you’ll be prompted for whichever comments you want to add. These will be added to the Finder Spotlight comments of the files for these messages, and will immediately be available in global Spotlight searches.
Note: a bug has been found with Mail.app handling of moved messages. MessageLaser comments are lost if the message is moved. MessageLaser development has been discontinued; I recommend Indev’s MailTags.
Freeware, suggested donation: $10
Requires: Mac OS X 10.4