§Your friend phpinfo().
Phpinfo is a little tool to inspect your PHP install.. It tells you what version is running, whether or not the ghastly safe_mode or the horrendous open_basedir-restriction is in effect.
What you should do is upload a small file called phpinfo.php to your webserver, and access it through your browser. If your server does not run php, it will look like this:
<?php echo "version is: <b>".phpversion()."</b><br>\n"; echo "Lots of info: <br>\n" phpinfo(); ?>
If, however, you get a screen like this, you have a working PHP install:
It will tell you the version of your PHP install, the typ eof server it is on, and whether or not it is running in safe_mode.