There is only one telefone and mobile (monopol) operator in the United Arab Emirates named ETISALAT. Local telephone calls from one telephone line to another are not charged. Mobile network works on a 900 Mhz frequence.  

UAE country code: +971

Back to SMS, it used to be that if you wanted to send SMS thru internet to somebody who has Etisalat SIM card, you could browse the following web page, this servise is nowadays still and still unavailable:(

http://www.wapcardz.com/sms.php3