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.

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 ...

Windows/Mac/Linux (All platforms): Free and open-source virtualization tool VirtualBox recently released a 2.0 version that includes a few major upgrades. Most importantly, 2.0 supports running 64 ...

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 ...