Help setting up/running a free email service

I'm trying to get a free email service (supported by textads) up and running supplying @potmaster.com accounts, but so far I've drawn a blank as to how to work the damn thing.

Basically, at the moment I have the website (www.potmaster.com) where people can fill in a simple registration form and get an @potmaster.com account that automatically forwards all emails to their chosen existing email address - e.g. for people who have something like [email protected].

Now at the moment I can handle all registrations manually (actually, ahem, there haven't *been* any proper registrations yet, just junk ones!), but I'd like to have some sort of automated process, especially if people start signing up in greater numbers.

Eventually, I'd also like to have a secure webmail script (ala Squirrel Mail) that is easy to install/customise (because I'll want to integrate textads and other stuff into it), and doesn't use up a lot of bandwidth.

Does anyone please have any suggestions/ideas/comments on how to go about this? Apologies if I've been a bit vague, I don't really know how to explain in detail what I want to do (basically: run free forwarding accounts, free webmail-based & ad supported accounts, and maybe [eventually] paid-for POP3 accounts).

BTW, I don't want any software that requires a specific mail-server, needs compiling on the server or anything along those lines, because I'm just starting out with web-based email (and my server is shared, so I can't easily install software, especially if it requires compilation).

talk to Microburn - he runs his own email server so should be able to help out