In Linux they are called workspaces. In Mac they are called spaces. Although they have different names they are the same thing. Virtual desktops help you reduce clutter on your desktop by allowing you to group your application windows according to the way you work and easily switch between them. Unfortunatelly Windows 7 and Windows Vista don't have such a thing. So here comes VirtualWin and nSpaces, two freewares that will allow you to add workspaces on Windos 7 and Windows Vista.
nSpaces is a free and lightweight software for Windows that allows you to add virtual desktops functionality. The default number of virtual desktops is 4, however you can add as many as you want. Here are the main features of nSpaces:
And here is the modules list of VirtualWin. KvasdosPager, VMPreview and VirtualWallpapersPlus will make your Windows desktop behave like Linux's..
I've tested both programs and I have to say that VirtualWin has much more options and no lag, unlike nSpaces. However if you want a simple software to change between virtual desktops nSpaces will do the job. Are you using any similar software?