Today there are hundreds of websites which offer sending SMS services in India & abroad. The drawback with most of these websites is  that they dont work out until you buy some SMS credits.Here is the list of some best websites by which you can send SMS to Mobiles across the worlds for Free of Cost !!

1. 160by2 a service which was started a year back and has become a huge hit because of their excellent features. It allows you to send in a SMS message to any mobile phone in India which is 80 characters long and they automatically attach a 80 characters sized text based relevant[contexual] advertisement in order to make money from this service.
2. Way2SMS is another free SMS sending service which offers more SMS sending characters limits which is upto 92 characters and thats more better than 160by2 sms service.
3. Jaxtr is a service which was launched in March 2007 which has a real huge membership of 10 million + with members from around 220 countries and they not only offer free sms service but also offers free calls recieving from all over the world making it the worlds largest talk network.
4. GizmoSMS is another free International SMS service using which you can send a SMS to any country all over the world. Even though there are no charges for sending a SMS but the reciever may get charged for recieving a SMS and this depends on the carrier and their services. This service also offers a feature of free calls where you can call up the person whom you have sent a free SMS.
5. Atrochatro is a free sms sending service with a twist, which means they not only offer free sms sending to india but also offers numerous other services like free SMS samples for different occassions with games, free-ecards and lot more.
6. IndyaRocks is a social networking website whose one small feature is sending SMS to registered members all over the world. They offer Group SMS service by sending a SMS to all your friends at the same time which may be useful at times of occassions and every verified and registered member in your group can recieve your sent SMS.
7. Text4Free : Text4free is a free SMS & MMS Sending service from your computer with international sending features and also to update Myspace.
8. Wadja – Worldwide coverage, need registration.
9. Peekamo – Worldwide Free SMS
10. OOSms – Worldwide Free SmS – registration needed.

Note : This list will be constantly updated. All the sites are working at the time of writing this post .Please let me know if any of them are not working or are turned to be a premium site. Also update me if you find any similar service available via Comments.