According to freebsd.org, 11.0-RELEASE is still in the build stage and awaiting a release announcement this Wednesday. However, release builds have appeared on the FTP site:
ftp://ftp.freebsd.org/pub/FreeBSD/releases/amd64/amd64/ISO-IMAGES/11.0/
This is obviously unofficial, and use them at your own risk.
At time of writing, the ARM and i386 versions is also available but not yet the PPC, ia64 or Sparc.