Usually, I used two or more virtual desktop on mac osx (before snowleopard). Commonly, we can use virtual desktop using "control and right or left arrow button." However, after the lion, i could not find any virtual desktop. Today, I find this virtual desktop function on lion. On default, there is only one virtual desktop. When you press F3 button, you will be able to see all windows at same time. On this screen, you will see + button top and left side of the screen, when you move mouse cursor to the point. Then click the button. You will be able to use several other virtual desktop. For the removing the optional virtual desktops, you just need to push x button on the list of virtual desktop on the top of screen.
I don't know....... You don't know........who know.....???