A set of 12 patches were published on Friday to start off Wayland support for FreeBSD. The patches begin here on the Wayland mailing list.
The changes come down to mostly adding in support for various functions on FreeBSD to replace their Linux equivalents used by Wayland. However, even if Wayland and Weston end up working on FreeBSD, the support won't be too widespread considering the only kernel mode-setting driver ported to Wayland in the mainline kernel is the Intel KMS driver as of FreeBSD 9.1.
We'll see how long the FreeBSD Wayland work goes on, but chances are it won't see much attention or gain much ground on the FreeBSD desktop.