Hi,
Personally, for such a setup - I'd go with postfix-mysql + cyrusimapd, and for webadmin you can throw in web-cyradm. That will let you manage virtual users / domains / forwards / autoreplies etc
This one is include in the base CentOS right? have any link for intergrade those applications?
One of the most recommended setup's to combat spam, cheaply, seems to be implementing greylisting within postfix. In most cases that reduced your spam intake by almost 98% without any extra cost on cpu or bandwidth.
For antivirus filtering take a look at MailScanner ( http://mailscanner.info/ ) it integrates well into CentOS3 or 4. And can work with most antivirus scanners that work on Linux.
Johnny has a couple of excellent guides on his website at http://www.hughesjr.com/
- K
Thanks for the links, I will check it later this day..
Thanks In Advances, Regards, ijez