VMware is the leading product in desktop virtualization. It acts as a virtual computer, in which you can install any operating system of your choice. Apart from testing a new OS before installing it into the actual PC, you can use this program to do any work that you think may damage your actual system, like hacking, trying out viruses, etc.
One of its most notable features is the drag and drop functionality, which allows you to copy files directly from the virtual OS to the host OS or vice versa. But while files are being copied, you can't use your PC at all.
In addition, to get this feature you should install the VMware tools program into your computer. This set of tools helps you better integrate the VMware client into the host OS. You can also create a virtual network with some virtual clients and the host. NAT, bridged connection, etc. can be easily set up too.
VMware Workstation 7.0 includes a lot more features than the previous versions. In this version the networking functionality and the support for new operating systems have been greatly improved .
Additionally, VMware Player is included in this package. This add-on is very useful, if you want to run multiple operating systems at the same time on your computer such as Windows 7, Chrome OS or the latest Linux. The player also can run an older version of your OS.
One of the newest features included in the player is the "unity mode", which allows to run some virtual applications from the task bar of the host OS. This mode is somewhat slow, but it doesn't cause any problems with any operating system, except for Linux. If you enable "Show position of pointer when the Control key is pressed" option in System > Preferences > Mouse in this OS, the mode might not work correctly.
I really like the VMware Workstation program. It is a suitable tool not only for the professional programmers, but also for every user who is fun of searching for a lot of programs on the net and testing them out.