Hi
http://www.muktware.com/bitsnbytes/3027
"Preupgrade provides an upgrade directly to the latest version of Fedora. It is not necessary to upgrade to intermediate versions. For example, it is possible to go from Fedora 11 to Fedora 13 directly. PreUpgrade is stable and is available in all current Fedora releases. While PreUpgrade downloads the necessary packages, users are free to continue using their systems. This gives an experience similar to a live upgrade."
Rahul
marketing@lists.fedoraproject.org