How to back up my minecraft maps?

Its just incase something bad happens

Added (1). i have a macbook how do i do it on that

-Go to C:\Users\username\AppData\Roaming\.minec…
-Find the File called SAVES
-Right click the file and click copy
-Paste the file anywhere on your PC.

Viola! Backed-Up!

Cheers!
-TheJavaWalkie

I believe the Mac stores the files in ~/Library/Application Support/minecraft

If you search for that you should find it without a problem.

In Windows the Roaming file is traditionally hidden, Find the "Run" Tool, (in the Start Menu in XP) or (press CTRL+R) or (Press Windows Key+R, in windows 8)
-type %appdata% in the Run window, press enter
-click.minecraft folder
-Saves Folder
then copy The folder with the same world name and save it elsewhere