[Exim] Hi. moving to maildir. looking for suggestions

i need to move from one mail server running standard /var/mail delivery,
to a new box using maildir.

what would you people suggest as a way to move the files from one server
to another? Should I tar the /var/mail contents, then ftp, then find a
script to convert the format and drop them into the
/home/username/Maildir?
what about sending all mail from one server to another (i remember there
is a way to do this with exim) and have exim create the Maildirs in the
users home directories.. What about just leaving the files in /var/mail
and converting to mail dir in that directory as opposed to home dirs?

any help would be appreciated..