I guess it'd be pretty hard for an auto responder. The ftp would have to create it's own account, apache, it's own virtual host, and much more.
So I'm guessing that you do it manually.
I think for myself, since I'll just be hosting locally I don't really need a big billing system.
We use Clientexec, which when combined with DirectAdmin does the above.
Starting off small and local can be done without a billing system, but I would recommend you get one anyway - the licences really aren't that much and the amount of time and energy you save is well worth it. It also gives a much more professional face to those clients which know a little about what they're dealing with.
DirectAdmin does all the legwork as far as creating virtual hosts, email accounts and ftp accounts (and all the rest), ClientExec just feeds it a username and a password to create an account with. We still activate them manually, so that we can do some last minute fraud screening, but it can be fully automated.