Mauricio Tavares wrote:

If users are checking their email using imap or pop, is there a 

way they can change their own passwords (so I can create a temporary one and let them change them to whatever they want) through, say, Thunderbird or whatever?

Imap and pop3 protocols don't have such functions - dovecot too. Actually there is no "standard" user/password database for Dovecot. It supports a lots of different auth databases. Plain text, SQL LDAP etc.The way you change password depends on database you are using.

I use SquirrelMail web mail - it have plugins for most auth db formats (PAM ,SQL, LDAP). In may case it is my own written wrapper/plugin as I use mixed auth sources. User must log in with current password to change it.

Uldis