From Facebook Developer Wiki

A step-by-step guide to setting up the Smiley sample app for the new profile. This assumes you are on a machine with PHP5 and SVN, which should be included on most hosts. It doesn't require a database or any other dependencies.

For this example, let's say we have a server with URL www.example.com.

Check out the code from our public page an externally accessible directory (public_html or similar) by running:

or download it from http://svn.facebook.com/svnroot/platform/samples/packages/smiley.tar.gz.

You also need to download the latest Facebook client and replace the facebook.php and facebookapi_php5_restlib.php files in the smiley directories.

Now create a new Facebook application. Fill out a name and then expand the options. You need to specify a Canvas Page URL and select FBML for the Render Method. In our case, the URL is mysmiley/.

Go into the Smiley config directory and copy settings.ini.sample to settings.ini.

Edit settings.ini. It has 4 fields: ROOT_LOCATION, APP_SUFFIX, API_KEY, SECRET_KEY. The ROOT_LOCATION is the callback URL to your application (in the example, it's http://www.example.com/smiley/), APP_SUFFIX is the URL you entered on the application settings page (mysmiley/). And the other two fields are the API_KEY and SECRET_KEY assigned to your application when you created it.

When you are done, run:

This sets up your application, creates Feed stories, and sets some default info fields.

You should now be ready to go. Visit apps.facebook.com/{canvas URL} to check out the application.