Parallels virtual machine allows users to run multiple operating systems (Windows, Linux, FreeBSD, OS/2 etc.) in independent virtual machines on a single physical computer. Products, support, download.

An x86 virtualization software package developed by Sun Microsystems. Distributed under either the GNU GPL or a proprietary license with additional features.

XenSource enables enterprise-grade virtualization and is the home of the open source Xen hypervisor project. Description, community, company.

An open source emulator for all popular architectures and operating systems.

Alessandro Perilli's blog covering Microsoft, VMWare and related virtual machine products.

Virtual x86 Computer for Macs, runs instead of Mac OS for better performance.

An online publication for news and information on virtualization technologies.

David Marshall's Blog covering virtualization news and technology information such as from VMware, Xen, SWsoft and Microsoft.

A pure Java emulation of an x86 PC with fully virtual peripherals, licensed under the GNU GPL. Describes the implementation and shows some screenshots as well as online-versions of the emulator running FreeDOS and GNU/Linux.

Provides a virtual computer that can be run from USB flash drive without installing anything on the desktop computer.