Presently, VirtualBox runs on Windows, Linux, Macintosh and OpenSolaris hosts and supports a large number of guest operating systems including but not limited to Windows (NT 4.0, 2000, XP, Server 2003, Vista, Windows 7), DOS/Windows 3.x, Linux (2.4 and 2.6), Solaris and OpenSolaris, and OpenBSD.
The latest Ubuntu release is for 9.10. Dunno the status of a version for 10.4 - http://www.virtualbo...i/Linux_Downloads
HTH a little.
Cheers,
Scott.