Automating the migration of users

Hi,

I'd like to know if there is a sample script that I could customize in order to migrate my domains/email accounts.

My virtual domains use a translation table to sotre the emails.

example. user@foo.com
pop3 user: userfoo

My passwords are stored in DES or MD5 so I'd like to have an automated way to insert those accounts without having to reset the password or change the username.

Regards.