Top Alternatives to VMware Fusion

VirtulaBox is an open source software to run virtual systems on top of a physical system. Virtual systems are normally used for providing separate environment for each client sharing a single physical system.

VMware Workstation is a hosted hypervisor that runs on x64 versions of Windows and Linux operating systems.

VMware Workstation Player, formerly VMware Player, is a virtualization software package for x64 computers running Microsoft Windows or Linux.

Parallels Desktop for Mac, by Parallels, is software providing hardware virtualization for Macintosh computers with Intel processors.

Kernel-based Virtual Machine (KVM) is a virtualization infrastructure for the Linux kernel that turns it into a hypervisor. It was merged into the Linux kernel mainline in kernel version 2.6.20.

Portable-VirtualBox is a free and open source software tool that lets you run any operating system from a usb stick without separate installation.

MobaLiveCD is a freeware that will run your Linux LiveCD on Windows thanks to the excellent emulator called "Qemu".

Boot Camp Assistant is a multi boot utility included with Mac OS X that assists users in installing Microsoft Windows operating systems.

Wineskin Winery is a tool for Wineskin.

Bochs (box) is a portable IA-32 and x86-64 IBM PC compatible emulator and debugger mostly written in C++ and distributed as free software under the GNU Lesser General Public License.