If you connect to telco, it will probably be SMSC directly through SMPP or similar protocols, which means you will need to configure something to talk to it. Kannel is a great open source SMS gateway implementation, and probably your best bet. It takes care of the conversation with telco SMSC and provides you with a simple HTTP interface for sending messages from your application.
In this case, you better try to configure it sooner rather than later, because it is involved in configuring Kannel quite a bit. This requires Linux-based systems to work, and no Windows port.
, , SMS-, HTTP-, Kannel, . - - , , - "55124" . HTTP- sms:
http://smsgateway.local/simulator.php?to=12345678&from=12345&body=hello+there
. sms , , SMPPSim, , .