note 624 added to signals.connection.php

Try this class based example. Hope you'll enjoy.
<?php
if( !extension_loaded('gtk')) {	
    dl( 'php_gtk.' . PHP_SHLIB_SUFFIX); 
}

class c_win extends GtkWindow
{
	function __construct($parent = null)
	{
		parent::__construct();
		$this->connect("destroy", "shutdown");
		$this->set_border_width(10);
		$this->set_default_size(-1,500);
		
		$this->add($this->_Box());

		$this->show_all();

	}

	function _Box()
	{
		$box = new GtkHBox();
		$fram_horiz = new GtkFrame("New Horizontal Button");
		$box->pack_start($fram_horiz,true,true,10);
		
		$button = &new GtkButton("Click Me!");
		$button->connect("clicked",array($this,"button_clicked"));


		$fram_horiz->add($button);

		return $box;
	
	}
	
	function shutdown() 
	{
	    print("Shutting down...\n");
	    gtk::main_quit();
	}

	function button_clicked()
	{
		    $window = &new GtkWindow();
		    $label = &new GtkLabel("You clicked the button");
		    $window->add($label);
		    $window->connect("destroy",array($this,"shutdown"));
		    $window->show_all();
		    return false;
	}
}

$win = new c_win();
Gtk::main();

?>

 http://gtk.php.net:80/manual/en/signals.connection.php