Some of the great features in Ubuntu 9.04 include: ext4 support, new login screen, some new wallpapers, faster boot-time and updated versions of software.
NOTE: Install this version of Ubuntu only on your Personal Computer. Because it is still in Beta you might experience some bugs.
To upgrade your existing installation simply press Alt+F2 and type "update-manager -d" (of course, without the quotes). A window will pop out telling you a new release is available. Press upgrade and wait.
If you want to install Ubuntu 9.04 Beta from scratch on your PC or on a virtual machine please see the download links below.
ubuntu-9.04-beta-desktop-i386.iso (CD, x86) ubuntu-9.04-beta-desktop-amd64.iso (CD, AMD64)