The Ubuntu 11.04 VMware image (http://www.trendsigma.net/vmware/ubuntu1104.html) is the first that officially supports Unity, the new desktop environment from Ubuntu. Being a VMware image, it is necessary to have a virtual machine for running it, for instance the VMware Player (http://www.trendsigma.net/vmware/vmwareplayer.html), which is free. Here is some more info about VMware and how to use its virtualization infrastructure (http://www.trendsigma.net/vmware/).