How to see how much HD space left on my Macbook?

I have a macbook osx, not one of the new 13 inch ones, and I want to get the Sims 3, but im not sure if I'll have enough space! how do i find out how much space I have?

Highlight the icon for your hard drive by clicking on it. Then press command+i and a window will display info about the drive, such as space used and space available. This works to check the size of documents and folders as well.