HELP PELEAS -- littel modification -- mail() to smtp

(MY ENGLISH IS NOT GOOD)
I found a script that send rss to email and i am a beginner in php and i want some one make this script send from smtp (smtp.gmail.com) FOR ME PLEASE and THANKS in advance

<?php
    /**
    * o------------------------------------------------------------------------------o
    * | This package is licensed under the Phpguru license. A quick summary is       |
    * | that for commercial use, there is a small one-time licensing fee to pay. For |
    * | registered charities and educational institutes there is a reduced license   |
    * | fee available. You can read more  at:                                        |
    * |                                                                              |
    * |                  http://www.phpguru.org/static/license.html                  |
    * o------------------------------------------------------------------------------o
    *
    * © Copyright 2008,2009 Richard Heyes
    */

    /**
    * Some RSS feeds to fetch. It uses a UNIX tmp dir which you will need to change if you're using it on Windows.
    */
    $urls[] = 'http://www.phpguru.org/rss.php';
    $urls[] = 'http://www.planet-php.org/rss/';

    foreach ($urls as $url) {
        $rss    = file_get_contents($url);
        $xml    = new SimpleXMLElement($rss);
        $cache  = '/tmp/rss_' . md5($url) . '.txt';
    
        /**
        * Get the cache file. Could replace this with an "inRSSCache()" function
        */
        $cache_contents = file_exists($cache) ? file_get_contents($cache) : '';
    
        /**
        * Some stuff to use in the email
        */
        $feed['title']        = (string)$xml->channel[0]->title;
        $feed['link']         = (string)$xml->channel[0]->link;
        $feed['description']  = trim((string)$xml->channel[0]->description);

        /**
        * Print the data
        */
        header('Content-Type: text/plain');
        echo 'Feed: ' . $feed['link'] . "\r\n";

        /**
        * Loop through all the items in the feed
        */
        foreach ($xml->channel->item as $item) {
            $url = (string)$item->link;
            
            if (strpos($cache_contents, $url) !== false) {
                continue;
            }

            echo "      {$url}\r\n";
            
            // The data from the feed
            $title       = (string)$item->title;
            $link        = $url;
            $pubDate     = (string)$item->pubDate;
            $description = ltrim($item->description);

            $to   = 'postmaster@domain.com'; // Put your email address here
            $mail = <<<END
Title: {$title}
  URL: {$url}
 Date: {$pubDate}
 
{$description}
END;
            mail($to, '[RSS] ' . $title, $mail, "From: {$feed['title']}"); // Might want to put a valid From: address here
                                    
            // Store the URL in our tmp file for recording which items we've seen
            fwrite(fopen($cache, 'a'), $url . "\r\n");
        }
    }
?> 

PHP:

 

Take a look at the pear package and this article
http://email.about.com/od/emailprogrammingtips/qt/PHP_Email_SMTP_Authentication.htm