VirtualBox is flexible enough to handle many types of 32-bit and 64-bit configurations. If you need to run a 32-bit version of XP in a 64-bit host, you can do that without any problems.

Sun xVM VirtualBox 2.0 is available now for Mac OS X (all versions, Intel hardware only), Windows (32- and 64-bit XP, Vista, and Server 2003 and 2008), Linux (several flavors), and Solaris (32- and 64 ...

If VirtualBox is not showing 64-bit Operating System, Enable Hardware Virtualization or Disable Hyper-V. More suggestions are here in this post.

VMware has a press release on their website that announces the release and availability of version 3.0 of Fusion, which brings 64-bit support along with other enhancements to the software.

Want to run Windows 8's recently released Consumer Preview as a virtual machine? This guide will walk you through the process using the free hypervisor VirtualBox.

The Windows 8 beta is here. This is what you need to know to run it in a virtual machine in VirtualBox.