Generally, the goal of the project is to enable the conversion of .msg files into standards based formats, without reliance on outlook, or any platform dependencies. In fact its currently pure ruby, so it should be easy to get running.

It is targetted at people who want to migrate their PIM data from outlook, converting msg into rfc2822 emails, vCard contacts, iCalendar appointments etc. However, it is also a complete msg library, providing a sane model for (currently read-only) access.

The project is also home to a very basic class for manipulating Mime messages. This may get enhanced and spun off eventually.

Conversion of msg files:

gem install ruby-msg
msgtool -c some_email.msg > some_email.eml

Or to convert a bunch of msg files into mbox format (handles From quoting), and insert a delivered header:

msgtool -m -d 'Delivered-To: username@domain.com' *.msg > mbox

See the wiki for further details

I am happy to accept patches, give commit bits etc.

UPDATE: now have work-in-progess pst file format support (outlook 97 only currently, with 2003 support maturing). upcoming version 1.4 release will be a more general Mapi library, with both Msg and Pst backends.