While Arch Linux and others already ship Wayland packages, the plan for Fedora 20 is to have it be in a decent shape to serve as a "tech preview" for enthusiasts. Wayland would be shipped as an optional feature where users could opt for a Wayland session from the GDM (GNOME Display Manager) rather than an X.Org Server, which will still be present in Fedora Linux.
Fedora 20 will be shipping GNOME 3.10, which has good Wayland support with improvements from the GTK+ tool-kit to the GNOME Shell acting as its own Wayland compositor to Mutter improvements and a whole lot more, as covered in many Phoronix articles.
With having a full desktop to run under Wayland, and Red Hat being a big backer of GNOME, it's time in the Fedora world to play with Wayland. Christian Schaller of Red Hat wrote on his blog a Fedora Wayland update.
With GNOME 3.10 and the Wayland Tech Preview for Fedora 20, there will still likely be some GNOME applications that haven't yet been fully ported to Wayland. Additionally, the support state of XWayland on Fedora 20 is still uncertain.
Fedora developers do eventually intend to switch to Wayland by default, but it hasn't yet been decided whether that will happen for Fedora 21 or when the migration by default away from an X.Org Server will happen, which developers want to be a seamless experience.