[SLE] Account sign up tools

[Anders Norrbring]

Hi!
First of all, sorry for x-posting, but this question doesn't really fit in
anywhere...

I'm looking for a tool to enable users to sign up for an e-mail account.
I'm going to open up a mail hosting service and I need some engine that can
check an entered user name with the existing database so the new user can
continue registration.

I don't want any automatic account creation, just a check in the existing
users database to see if the e-mail address is available or already taken.

My e-mail system is based on Postfix, Cyrus, Web-Cyradm with a MySQL back
end.  I know that this should be really simple to do with a check in the
MySQL data base from a php page, but I'm not at all knowledgeable in php.

Anders.