I'd like to add some thoughts about the curl-based answer of Fred Tanrikut. I know most of them are already written in the answers above, but I think it is a good idea to show an answer that includes all of them together. 
Here is the class I wrote to make HTTP-GET/POST/PUT/DELETE requests based on curl, concerning just about the response body:
class HTTPRequester {
    /**
     * @description Make HTTP-GET call
     * @param       $url
     * @param       array $params
     * @return      HTTP-Response body or an empty string if the request fails or is empty
     */
    public static function HTTPGet($url, array $params) {
        $query = http_build_query($params); 
        $ch    = curl_init($url.'?'.$query);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HEADER, false);
        $response = curl_exec($ch);
        curl_close($ch);
        return $response;
    }
    /**
     * @description Make HTTP-POST call
     * @param       $url
     * @param       array $params
     * @return      HTTP-Response body or an empty string if the request fails or is empty
     */
    public static function HTTPPost($url, array $params) {
        $query = http_build_query($params);
        $ch    = curl_init();
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HEADER, false);
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $query);
        $response = curl_exec($ch);
        curl_close($ch);
        return $response;
    }
    /**
     * @description Make HTTP-PUT call
     * @param       $url
     * @param       array $params
     * @return      HTTP-Response body or an empty string if the request fails or is empty
     */
    public static function HTTPPut($url, array $params) {
        $query = \http_build_query($params);
        $ch    = \curl_init();
        \curl_setopt($ch, \CURLOPT_RETURNTRANSFER, true);
        \curl_setopt($ch, \CURLOPT_HEADER, false);
        \curl_setopt($ch, \CURLOPT_URL, $url);
        \curl_setopt($ch, \CURLOPT_CUSTOMREQUEST, 'PUT');
        \curl_setopt($ch, \CURLOPT_POSTFIELDS, $query);
        $response = \curl_exec($ch);
        \curl_close($ch);
        return $response;
    }
    /**
     * @category Make HTTP-DELETE call
     * @param    $url
     * @param    array $params
     * @return   HTTP-Response body or an empty string if the request fails or is empty
     */
    public static function HTTPDelete($url, array $params) {
        $query = \http_build_query($params);
        $ch    = \curl_init();
        \curl_setopt($ch, \CURLOPT_RETURNTRANSFER, true);
        \curl_setopt($ch, \CURLOPT_HEADER, false);
        \curl_setopt($ch, \CURLOPT_URL, $url);
        \curl_setopt($ch, \CURLOPT_CUSTOMREQUEST, 'DELETE');
        \curl_setopt($ch, \CURLOPT_POSTFIELDS, $query);
        $response = \curl_exec($ch);
        \curl_close($ch);
        return $response;
    }
}
Improvements
- Using http_build_query to get the query-string out of an request-array.(you could also use the array itself, therefore see: http://php.net/manual/en/function.curl-setopt.php)
- Returning the response instead of echoing it. Btw you can avoid the returning by removing the line curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);. After that the return value is a boolean(true = request was successful otherwise an error occured) and the response is echoed. 
See: http://php.net/en/manual/function.curl-exec.php
- Clean session closing and deletion of the curl-handler by using curl_close. See: http://php.net/manual/en/function.curl-close.php
- Using boolean values for the curl_setopt function instead of using any number.(I know that any number not equal zero is also considered as true, but the usage of true generates a more readable code, but that's just my opinion)
- Ability to make HTTP-PUT/DELETE calls(useful for RESTful service testing)
Example of usage
GET
$response = HTTPRequester::HTTPGet("http://localhost/service/foobar.php", array("getParam" => "foobar"));
POST
$response = HTTPRequester::HTTPPost("http://localhost/service/foobar.php", array("postParam" => "foobar"));
PUT
$response = HTTPRequester::HTTPPut("http://localhost/service/foobar.php", array("putParam" => "foobar"));
DELETE
$response = HTTPRequester::HTTPDelete("http://localhost/service/foobar.php", array("deleteParam" => "foobar"));
Testing
You can also make some cool service tests by using this simple class.
class HTTPRequesterCase extends TestCase {
    /**
     * @description test static method HTTPGet
     */
    public function testHTTPGet() {
        $requestArr = array("getLicenses" => 1);
        $url        = "http://localhost/project/req/licenseService.php";
        $this->assertEquals(HTTPRequester::HTTPGet($url, $requestArr), '[{"error":false,"val":["NONE","AGPL","GPLv3"]}]');
    }
    /**
     * @description test static method HTTPPost
     */
    public function testHTTPPost() {
        $requestArr = array("addPerson" => array("foo", "bar"));
        $url        = "http://localhost/project/req/personService.php";
        $this->assertEquals(HTTPRequester::HTTPPost($url, $requestArr), '[{"error":false}]');
    }
    /**
     * @description test static method HTTPPut
     */
    public function testHTTPPut() {
        $requestArr = array("updatePerson" => array("foo", "bar"));
        $url        = "http://localhost/project/req/personService.php";
        $this->assertEquals(HTTPRequester::HTTPPut($url, $requestArr), '[{"error":false}]');
    }
    /**
     * @description test static method HTTPDelete
     */
    public function testHTTPDelete() {
        $requestArr = array("deletePerson" => array("foo", "bar"));
        $url        = "http://localhost/project/req/personService.php";
        $this->assertEquals(HTTPRequester::HTTPDelete($url, $requestArr), '[{"error":false}]');
    }
}