VirtualBox is a general-purpose full virtualizer for x86 hardware. Targeted at server, desktop and embedded use, it is now the only professional-quality virtualization solution that is also Open Source Software.
VirtualBox OSE is not crippleware. It’s as full-powered a virtualization program as you’ll find today. What it’s missing are additional features, not basic functionality. You can also use the proprietary version, without charge for personal and educational use and to evaluate it for possible business purchase.
The free, but proprietary, edition gives you a built-in RDP (Remote Desktop Protocol) server and USB port support. It also offers, to the best of my knowledge, the unique ability to use RDP to access remote USB devices from a local VM (virtual machine) and use local USB devices on a remote VM. It also supports the use of iSCSI network drives for use as virtual hard drives.
VirtualBox works on any PC with an x86 architecture. It also supports Intel’s VT-x and AMD’s AMD-V recently introduced hardware virtualization components. It does not, though, support either one by default. You must manually turn it on via the program’s control center.
While VirtualBox itself is lean-it will only take up 30MB of room on your hard drive-like any virtualization program, to use it successfully you’ll need multiple gigabytes of disk for the virtualized operating system and its files. In addition, you’ll need enough RAM for your base operating system and every VM instance. For example, to run Linux as a host with XP as a guest VM, you’d need at least a gigabyte of RAM. For Vista as a guest, you’ll need at least 2GB and so on.
See Review Here: http://www.techthrob.com/tech/linux_virtualization.php
Note Review [The above article compares four virtualization products available for Ubuntu Linux: the free, open source x86 emulator Qemu; the closed-but-free versions of VirtualBox and VMware-Server, and the commercial Parallels Workstation. ]