Although it’s not operated in some countries (yet?) I can find Indonesia is one of the supported countries.

How to do it:

1. Type the mobile number in the box

2. If it’s not saved yet into your contacts, then the following screen will pop up asking you to save the contacts

3. Type the message like usual in the chat box

Please note that Google gives us 50 per day. Every time we send out, it will decrease by one. Every time we receive a reply, it will increase by one. By the end of the day it will be reseted to default max credit 50.

Find out more from the original source: http://goo.gl/bFKVV

After experiment it, I can send SMS to my number and receive it successfully. However, when I tried to reply from my mobile phone it didn’t work. :/