[Dovecot] ldap authentication

Hi,

I have got Postfix, Dovecot IMAP and squirrelmail up and running on my ubuntu server 10.04 for a testing purpose. My question is in order to be able to login, do I need to create user accounts for each users on the server? I have about 20 users at the moment, and it's going to take time. I was thinking of using LDAP and have the dovecot authentication through LDAP. This way, I do not have to create accounts for 20 users on the server. The dovecot can just authenticate users by looking them up against the LDAP.

I wonder if anyone would be able to share some guides as to how to set it up to work with Postfix and Dovecot.

Thank you