XML Parser Basic Newbie question

Hi
I’m trying to parse an xml fed and extract some data to display in a form.
I found an excellent tutorial here which extracts the data ai need and places it in a varial $data
http://www.kirupa.com/web/xml_php_parse_beginner.htm
I’ve got this to work at http://www.bookbargains4u.com/xml_beginner.php

I can’t figure out how to extract the the individual lines from $ data eg. I’d like to be able to to put the book title in a form variable.
I asume I eill need some sort of substr command to do this but I’m struck
Can anyone help please?

TIA
Clive