I have a ColdFusion page that appends the a URL with form variables. I\'m trying replicate this code in php:
The HTTP PECL extension (which contains the HTTPRequest class) isn't part of a default PHP installation.
I would take a look at CURL: http://php.net/manual/en/book.curl.php. You can set the HTTP method and parameters.
Or, if you don't mind using a framework, checkout the Zend FW HTTP Client module: http://framework.zend.com/manual/en/zend.http.html
Here's an example of using CURL to do a post request: http://davidwalsh.name/execute-http-post-php-curl