Well, the thing is I don't have access to vpopmail directly - my web hosting service controls that. And I want the actual mailbox user to be able to change their own password. I went to the qmailadmin page and the demo showed an interface that looked more like an administrator interface rather than a mailbox user interface - which I already have from my hosting provider. Did I miss something? Any other ideas?
qmailadmin allows users to login into that interface and change their password.