With Ubuntu 8.04 the virt-manager and libvirt packages aren't on the CD, but only a step away in the repository. To get started, just run sudo apt-get install virt-manager libvirt-bin kvm. The libvirt daemon will automatically start and from there you can launch virt-manager and connect to localhost (or a remote machine running libvirtd, if applicable to your needs).
Once connecting to the virtualization backend, a graphical interface will guide you through the entire guest OS installation process. One of the first steps in the installation process is to select para-virtualization or full virtualization and selecting the guest CPU architecture. The CPU architectures currently supported are i686, x86_64, PowerPC, SPARC, MIPS, and MIPSEL. If the kvm-intel or kvm-amd kernel modules are loaded (for providing the KVM functionality), check the box for enabling kernel/hardware acceleration.
After selecting the guest architecture is a screen for locating the installation media and specifying the guest operating system type. Virt-manager supports loading an ISO image, CD-ROM or DVD, and a network PXE boot for loading the installation image. Selecting the operating system type is used for loading OS profiles, which will adjust the boot arguments according (such as whether to use ACPI). The operating system types listed are Generic, Linux, Other, UNIX, and Windows. The Linux variants currently include Debian Etch, Debian Lenny, Fedora Core 5, Fedora Core 6, Fedora 7, Fedora 8, Generic 2.4.x kernel, Generic 2.6.x kernel, RHEL 2.1, RHEL 3, RHEL 4, RHEL 5, SuSE Linux Enterprise Server, and Ubuntu Hardy. For the other type are Generic, MS-DOS, Novell Netware 4, Novell Netware 5, and Novell Netware 6. UNIX variants include FreeBSD 6.x, OpenBSD 4.x, Sun Solaris 9, and Sun Solaris 10. If you are still using Redmond software, the supported versions of Windows include Microsoft Windows Vista, Windows 2000, Windows 2003, and Windows XP.