This is not an ideal way to send SMS but it works, its easy and its free! Well not 100% free because to activate it the SMS receiver must dial 711. That will cost around Rs 3/-.
next go to your email program and create a new message.
in the 'To' field put the email address(es) in the following format
(this is the dialog number of the receiver followed by '@dialog.lk')
in the 'Subject' field put your message (this should be less than 120 characters)
leave message body blank
send the message
the receiver will get the message immediately.
This is an easy way to send short SMS alerts for free to a group of people. I found this method out while referring to the 'Pocket Office' service offered by dialog.
If anyone knows of a better way to send SMS for free to dialog please let me know. I tried out different services available online but none of them worked.