I've played around with CentOS 6.0 as well because I wanted to write a "Perfect Server" tutorial for CentOS 6.0 and ISPConfig 3. I had to stop because lots of packages seem to be missing, for example there's no getmail, and, even worse, no amavisd-new!
Maybe these packages will be available in a few days or weeks, but until then, the "Perfect Server" will have to wait.