Upgrade Tool Docs:
http://wiki.centos.org/TipsAndTricks/CentOSUpgradeToolMake sure you listen to the tool if it tells you that you have Medium,
High, or Extreme issues and mitigate them before trying to upgrade.
You can not upgrade if you have a GNOME or KDE desktop, for example.
Let's give this a try and hopefully we can move this out of testing and
into Extras next week.