MailArchive 1.1 (Mac)
Source: Flying Titans
Mail cannot save multiple messages through the "Save As…" menu item, therefore MailArchive was built to archive all the messages in Mail in a simple manner while preserving the folder structure that has been set up. MailArchive will use the date recieved, the flag marker, and if the message has been read or not to select a message for archive. Then after the message has been successfully archived the message may be moved to the trash for easy deletion. The messages are stored in mbox files that may be read by most mail programs.