Example #1 A classic Application directory layout
- index.php 
- .htaccess 
+ conf
  |- application.ini //application config
- application/
  - Bootstrap.php   
  + controllers
     - Index.php //default controller
  + views    
     |+ index   
        - index.phtml //view template for default action
  + modules 
  - library
  - models  
  - plugins 
Example #2 Entry
index.php in the top directory is the only way in of the application, you should rewrite all request to it(you can use .htaccess in Apache+php_mod)
<?php
define("APPLICATION_PATH",  dirname(__FILE__));
$app  = new Yaf_Application(APPLICATION_PATH . "/conf/application.ini");
$app->bootstrap() //call bootstrap methods defined in Bootstrap.php
 ->run();
?>
Example #3 Rewrite rule
#for apache (.htaccess)
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .* index.php
#for nginx
server {
  listen ****;
  server_name  domain.com;
  root   document_root;
  index  index.php index.html index.htm;
  if (!-e $request_filename) {
    rewrite ^/(.*)  /index.php/$1 last;
  }
}
#for lighttpd
$HTTP["host"] =~ "(www.)?domain.com$" {
  url.rewrite = (
     "^/(.+)/?$"  => "/index.php/$1",
  )
}
Example #4 Application config
[yaf] ;APPLICATION_PATH is the constant defined in index.php application.directory=APPLICATION_PATH "/application/" ;product section inherit from yaf section [product:yaf] foo=bar
Example #5 Default controller
<?php
class IndexController extends Yaf_Controller_Abstract {
   /* default action */
   public function indexAction() {
       $this->_view->word = "hello world";
       //or
       // $this->getView()->word = "hello world";
   }
}
?>
Example #6 Default view template
<html>
 <head>
   <title>Hello World</title>
 </head>
 <body>
   <?php echo $word;?>
 </body>
</html>
Example #7 Run the Applicatioin
The above example will output something similar to:
<html> <head> <title>Hello World</title> </head> <body> hello world </body> </html>
Note:
you can also generate above example by use Yaf codes generator, which could be found here yaf@github.