CHANGING THE POST DIRECTORY

By default on http://www.jeancarlohim.com when you try yo view a single post, on the url it will show something like http://www.jeancarlohim.com/?p=56 i want to change the http://www.jeancarlohim.com/ I want to change the ?p=56 for the name if the post like http://www.jeancarlohim.com/pymes-for-a-small-world how can I accomplish this