Unfortunately, at present time, we don't have direct ability to import eml into Notes nsf directly through the IBM Notes application.

   An enhancement for this ability has been logged with us,

   http://www-01.ibm.com/support/docview.wss?uid=swg21660000

   We could suggest opening a pmr with us and having an engineer add your additional interest onto the existing associated enhancement request spr to add weight on it's interest of being supplied as a feature in a new/upgraded release.

   At this time, Google searches on interest of importing eml into Notes nsf does provide some thoughts that might be of interest to you.

... however, we have to address this requirement (import of cca 700 GB of EML messages into Domino/Nots as part of migration project) within next month as "one time" activity.

Simply said: we cannot wait for "future" Domino/Notes release and have to find some "reliable" import script option (LScript, Java, etc.... MIME classes)....

As was said there are some code solutions out there.  I have used Binary Tree in the past(http://www.binarytree.com/home.aspx).  While not free you might want to give them a call if you have  a need to use a off the shelf solution vs a build solution.