The API-Documentation is available here:
http://pear.php.net/package/File_Bittorrent2/docs/latest/
Just see the provided example.php.
See scrape.php.
$ php scrape.php -t install-x86-universal-2005.0.iso.torrent Statistics ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Tracker: http://titmouse.gentoo.org:6969/announce info hash: f94b8d2d38632a6589d8121106059989f290b569 complete: 119 downloaded: 53452 incomplete: 16