I have purchased SMS gateway from one hosting company. How can i integrate my SMS gateway with my website?

If in case the SMS Gateway allows sending SMSes by a accessing a simple url with authentication etc params ( example:, http://<some third party sms gateway domain.com>/index.php?username=john@smith.com&password=randompassword&to=9876543210&message=testmessage)

then this all you need is
1. a simple html form
2. which can post the message
3. to a php script which can make a CURL call to the SMS Gateway URL

sample code for a CURL call

$url = "http://somethirdpartysmsgatewaydomain.com/index.php";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POSTFIELDS, 'username=john@smith.com&password=randompassword&to=9876543210&message=testmessage');
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result = curl_exec($ch);
echo $result;

Anyways, this is just A solution in case the SMS Gateway is operating in the above assumed fashion
Beyond this it would help checking out with the SMS gateway provider itself as to how all of this needs to be integrated

Any more info from them here would help

If in case the SMS Gateway allows sending SMSes by a accessing a simple url with authentication etc params ( example:, http://<some third party sms gateway domain.com>/index.php?username=john@smith.com&password=randompassword&to=9876543210&message=testmessage)

then this all you need is
1. a simple html form
2. which can post the message
3. to a php script which can make a CURL call to the SMS Gateway URL

sample code for a CURL call

$url = "http://somethirdpartysmsgatewaydomain.com/index.php";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POSTFIELDS, 'username=john@smith.com&password=randompassword&to=9876543210&message=testmessage');
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result = curl_exec($ch);
echo $result;

Anyways, this is just A solution in case the SMS Gateway is operating in the above assumed fashion
Beyond this it would help checking out with the SMS gateway provider itself as to how all of this needs to be integrated

Any more info from them here would help

Ok.. Thanks for your reply. Now i'm deling with the SMS gateway provider for the API.