How to Send free SMS with someone else's number

Ok, this my first tutorial so tell me what you think ;)
How to send SMS for free using someone else's number:
1. Go to Click Here
2. Select country
3. Fill in the form(when filling the senders ID make sure you include the numbers of your country in front)
4. Press send
5. Done!
Using this method I prank my friends all the time.
Please tell me what you think about my first tutorial.