VirtualBox received a major update a few weeks ago. The latest version 4.0 adds changes to the interface (now called VirtualBox Manager), new virtual hardware and a number of fixes which you can see in the changelog.
Here’s how you can update your existing Vbox 3.x installation on Fedora 14:
[root@localhost yum.repos.d]# cat /etc/fedora-release
Fedora release 14 (Laughlin)
[root@localhost yum.repos.d]# uname -r
[root@localhost yum.repos.d]# rpm -qa | grep -i virtual
[root@localhost yum.repos.d]# rpm -e VirtualBox-3.2
[root@localhost yum.repos.d]# yum install VirtualBox-4.0
The above commands will remove the old package, install the new one and compile the kernel modules. If you want to use USB 2.0 devices on your guests, you’ll also have to install the extension pack (available on the Downloads page).