there are 2 ways for sending sms:

- with GSModems (mobiles are in this category)
- with sms  service providers(usually via internet services)

Take a look at SMPP spec. It's so easy and very flexible

en....pedia.org/.../Short_message_peer-to-peer_protocol

you also can send  sms with smpp protocol if you have access to an smsc or sms-gateway or you can also send with third-party applications that normally provide a web service for this job.

Take a look at www.cs-networks.net.

They provide a cool app that allows you to send messages all over the world.

Regards,

recently i am creating a webservice in php that can send sms using way2sms gateway.
this is one grate way to send sms using java or php
for java code visit:---
and download java code...using json parser

http://youngstercarrer.com/smsapi/javasmsapi.php

if u wish u can use java httpconnection to send sms directly with following url.[ code can be find here.. http://youngstercarrer.com/smsapi/javasmshttp.php ]

youngstercarrer.com/.../sms_http.php?username="+ username +"&password="+ password +"&to=" + phoneNumber + "&msg=" + URLEncoder.encode(msg)