From Fedora Project Wiki
Fedora 11 added many development improvements, enhancements in automation, a step improvement in virtualization, and greatly enhanced security. If you just can't wait to see what Fedora 12 will have to offer, you can now get a peek at:
http://fedoraproject.org/get-prerelease
Of course, this is a beta release, so there might be things not quite right. Should you trip across one of them, be sure it gets fixed before release by reporting your discovery at:
What can I expect in Fedora 12?
- Improved Dual-Monitor Support - In Fedora 11, a desktop spanning multiple monitors worked with some video cards and some drivers. In Fedora 12, that support is extended to most video cards.
- Better Webcam Support - While Fedora 11 improved webcam support, in Fedora 12 you can expect even better video quality, especially for less expensive webcams.
- GNOME 2.28 - Fedora 12 includes the latest version of the GNOME desktop. A lighter Gnote now replaces Tomboy as the default note application, and Empathy replaces Pidgin as the default IM client. The new GNOME Shell gives you a taste of GNOME 3.
- KDE 4.3 - The new KDE has an updated "Air" appearance, with improved performance, and new desktop effects.
- Improved Networking - Support for mobile broadband has been improved, as well as better IPv6 support.
- Bluetooth on demand - In order to support Bluetooth devices, Bluetooth background service was started by default in previous versions of Fedora. In this release, Bluetooth service is started on demand when needed and automatically stops 30 seconds after last device use instead reducing initial startup time and resources.
- Fedora Studio - All the audio and video applications are categorized better on the menu, making it easier to find a specific application.
- Still more security improvements - Daemons which run as root have all been reviewed and patched to run with lower capabilities. This makes it even harder for an attacker to exploit a weakness in an application.
- Virtualization Improvements - Not content with all the improvements in Fedora 11, virtualization has been kicked up another notch in Fedora 12. There are improvements allowing virtual machines to better share resources, performance improvements, and management improvements. And of course, still more security improvements.
- Clustered Samba - Multiple instances of Samba running on different nodes in a cluster can now export a single filesystem to provide higher availability.
OK, go try it. You know you can't wait.