Run php script in cron ?

[Eminos]

Hi there,

I'm using WHMCS as a billing solution.
To use the automation stuff I need to add a line to cron.
I can choose between adding this:
php -q /var/www/virtual/somedomain.net/htdocs/whmcs/admin/cron.php

and this:
0 9 * * * GET http://www.somedomain.net/whmcs//admin/cron.php

Somehow the first options seems to be the better choise. But when I try running "php" I get:
-bash: php: command not found

I guess I need to install some stuff to get the php from command line working, right ?

/E