Two weeks ago at LinuxWorld conference Kevin Kettler, CTO at Dell, showed an OptiPlex 745 running Windows and Linux virtual machines on top of XenSource hypervisor.
Reports from sevearl news sources are vague and very different: InformationWeekk and others are reporting Dell will preload XenSource (now acquired by Citrix) hypervisor on its server line, while Linux Insider and others are reporting such offering will be available on consumers PCs as well, as soon as early 2008.
First scenario is very likely, considering Dell is working with VMware on upcoming ESX Server hardware appliance: the hardware vendor may want to offer more than one hypervisor to its customers.