Comes free with new Newtons. Unfortunately, the version that came with my Newton cannot use direct serial connections. A new version (1.4.1B1) is available from NetStrategy.
Here are the settings I have in EnRoute Settings in Owner Settings...
POP Username - newton POP host - amiga POP password - Tacobill SMTP host - amiga
Note that the EnRoute password is defined SEPARATELY from the password set in the Newton Internet Enabler preferences (which is the way it should be).
By contrast, the AmiTCP/popper combination uses the same password both for logon and the POP server.
Last modified 2nd August 1997.