I'm very interested in ISP-Config, it would solve a number of issues for my small company that runs it's own servers. Currently we use Qmail, and I understand ISP-Config does not support it. I'm disappointed because I've never really been able to grasp Sendmail comfortably, and I know even less about Postfix. I'm not really against either, just that Qmail made sense to my brain. I'm following the basic "The Perfect Setup - CentOS 4.4 (32-bit)" from right here at HowtoForge. It walks through setting up things such as BIND, Postfix, several other things that ISP-Config needs. In fact, ISP-Config is part of the tutorial. My question is this: After setting up Postfix and ISP-Config, email services are ready to go?
If you have setup your server according Falko's Perfect setup, you have everything you need for an ISP-server including a mailserver, which is ready to go.
Even if ISPConfig is Great, it's maybe not what your are looking for. If you want a mailserver for you Small Buisiness, I recomend you to have a look @ SME server http://www.smeserver.org. The last time I used it (many years ago) it was using Qmail.