Parsing a PHP file - Newbie alert

First post here so go easy on me please as I have looked in as many places as possible before resorting to this. I have installed MySQL, Apache 2.0.52 and PHP 4.3.10 on my XP Pro PC and have read through the installation docs etc to update httpd.conf as instructed. When I tried to run my first PHP file to show the PHP Info (<?php phpinfo(); ?>) the browser, Firefox 1.0 did nothing. I have placed the file in the htdocs folder as instructed. When I ran php -i from the command line, I got a html doc as I should have done, but still nothing in Firefox or IE6. Is there anythign else I should be trying to do or I can look at to try and resolve this? Many thanks Andrew H