I would like to be able to configure the WebMailFX module to operate with a catch all emaill address, thus providing my members with their own webmail accounts. How do I do this so the member's username is used as their email address? I don't want the members to be able to change their email address or configure to use a different POP3 server. I would also like m members to automaticaly be logged in to their mailbox when they go to the module.

It seems to me that what you're asking for is some features which are not actually in our plans. The module still didn't reached a 1.0 version: we're working on a 0.85 in our project page at dev.xoops.org. Nor is excluded that some additional features to what our roadmap to 1.0RCx stated (you'll find it in our project page) will be added before 1.0RCx. The point is we're really few people: adding features is not a problem when somebody gives it to us, but at present we're focusing on getting basic functions to work and securing the module.
Anyway: if you want to discuss WebMailFX related stuff, come to see us to:

http://dev.xoops.org/modules/xfmod/project/?group_id=1132

Bye,
ft