I noticed CentOS 6 is out. I downloaded CentOS-6.0-i386-netinstall.iso. So far it’s working flawlessly with Virtualbox.
For those that don’t have the netinstall URLs they are…
32 bit: http://mirror.centos.org/centos/6/os/i386/
64 bit: http://mirror.centos.org/centos/6/os/x86_64/