Fedora 10 Cambridge is set to be released on November 25th with ton’s of new improvements and features. If you are just as impatient and would like to upgrade to the preview release, without downloading the ISO files, simply update the release files and go through your standard update procedure.
[root@infamous ~]# rpm -Uvh ftp://ftp.uci.edu/mirrors/fedora/linux/releases/test/10-Preview/Fedora/i386/os/Packages/fedora-release-9.93-1.noarch.rpm ftp://ftp.uci.edu/mirrors/fedora/linux/releases/test/10-Preview/Fedora/i386/os/Packages/fedora-release-notes-9.92-4.noarch.rpm
You can use the graphical Software Update application or you can use yum from the console. `[root@infamous ~]# yum update
[…]
Transaction Summary

Install 92 Package(s)
Update 790 Package(s)
Remove 0 Package(s)`

Total download size: 994 M Is this ok [y/N]:
After it is done downloading and installing the packages you should be set and ready to go.