Fedora 16 Alpha
was released back in August, but today it has been replaced by Fedora 16 Beta.
Fedora 16 "Verne" will be officially released in November, but now it's time to test out the beta to ensure minimal bugs will be in this major Red Hat sponsored release next month. Among the prominent new features is the GRUB2 boot-loader finally being deployed, continued systemd work, GNOME 3.2 desktop, SELinux enhancements, finishing up the removal of HAL, and a great deal of work when it comes to virtualization. There's also the usual updates to the Linux kernel, Mesa / X.Org, GCC, and other interesting packages.
You can see a bit more about the Fedora 16 features via the Phoronix tour from August
Download links and the official release announcement are available from the Fedora Project's mailing list