function __autoload($classname)
{
    // put the path to your class files here
    $my_path = "/var/www/mydomain.com/lib";

    // tell PHP to scan the default include paht AND your include path
    set_include_path(get_include_path() . PATH_SEPARATOR . $my_path);

    // name your classes and filenames with underscores, i.e., Net_Whois stored in Net_Whois.php
    $classfile = str_replace("_", "/", $classname) . ".php";

    include_once($classfile);
}

/**
 * EXAMPLE:
 * create one of your objects, saved in /var/www/mydomain.com/lib/Project/Database.php
 */
$db = new Project_Database();


/**
 * EXAMPLE:
 * create a PEAR object, saved in /usr/local/lib/php/File.php
 */

$f = new File();

function __autoload($classname)
{
    // put the path to your class files here
    $my_path = "/var/www/www/mydomain.com/lib";

    // tell PHP to scan the default include paht AND your include path
    set_include_path(get_include_path() . PATH_SEPARATOR . $my_path);

    // name your classes and filenames with underscores, i.e., Net_Whois stored in Net_Whois.php
    $classfile = str_replace("_", "/", $classname) . ".php";

    include_once($classfile);
}

/**
 * EXAMPLE:
 * create one of your objects, saved in /var/www/www/mydomain.com/lib/Project/Database.php
 */
$db = new Project_Database();


/**
 * EXAMPLE:
 * create a PEAR object, saved in /usr/local/lib/php/File.php
 */

$f = new File();

function __autoload($classname)
{
    $my_path = "/var/www/www/mydomain.com/lib";
    set_include_path(get_include_path() . PATH_SEPARATOR . $my_path);

    $classfile = str_replace("_", "/", $classname) . ".php";

    include_once($classfile);
}

function __autoload($classname)
{
    $classfile = str_replace('_', '/', $classname) . '.php';
    include_once($classfile);
}

http://www.drewcking.com

__autoload is often used to load class files from a specific user-defined directory.  by simply adding the user-defined directory to the include_path, however, autoload can be used to load user class files as well as PEAR class files.  Assuming the PEAR naming convention is adhered to for the user defined classes.

using autoload with PEAR

PHP