The docs that were here were deleted primarily because of the fact that the script shown didn't backup the additional vpopmail directories they create. After about 25 (Earlier versions of vpopmail) or 90 (Newer versions of vpopmail) usernames were created, vpopmail started creating folders starting with 0, 1, 2, etc. This was to ensure that the main domain structure didn't get too populated.

The instructions below will backup all users and emails. This will NOT copy over ezmlm lists. This may happen in future releases.

On the old mailserver:

fetch http://goodcleanemail.com/files/tarballs/vpopmail_server_import_export.tgz
tar zxvf vpopmail_server_import_export.tgz
cd import
run backupemail.sh > output
create /home/backups/vpopusers
run CreateVPOPUserBK.sh
This places all the backups of vpopmail into the /home/backups/vpopusers dir
before you scp this folder over to the new server, make SURE you chown the user:group to the user you will scp it over to

On the new mailserver:

fetch http://goodcleanemail.com/files/tarballs/vpopmail_server_import_export.tgz
tar zxvf vpopmail_server_import_export.tgz
cd export
scp over the output file from the old mail server
mkdir /home/backups/vpopusers
Please note: Depending on how many domains/users there are, the next few commands can take several hours. Please plan accordingly.
scp the /home/backups/vpopusers from the old mail server to /home/backups/vpopusers on the new server
run output (This will create all the domains/users)
run RestoreTheUserDir.sh (This will restore all users folders)

All done!