[CentOS] Upgrade from CentOS 5.x to 6.0

Great news about CentOS 6.0 being available, and I figured I'd ask the most obvious question, what can I expect when upgrading from CentOS 5.6 to 6.0? I have not had to go from one major version of CentOS to another so this is new territory for me. Is the processes just like an install except there's an "Upgrade" option? Does an upgrade do a "yum update" of everything installed? Most of my systems use EPEL and some the IUS repos...is there a way during the upgrade to just upgrade system components and leave things like PHP, httpd and MySQL alone for now? Any suggestions on monitoring the upgrade progress via syslog or some other method so I can see exactly what is being done during the upgrade?

Thanks - Trey