To send mobile SMS, you need the respective library. In the below code, ActiveXperts SMS messaging APIs are used. You can download it from their page. Code is:
Dim objMessageDB, objConstants
Set objMessageDB = CreateObject("AxMmServer.MessageDB")
Set objConstants = CreateObject("AxMmServer.Constants")
objMessageDB.Open
objMessage.Type = objConstants.MESSAGETYPE_SMS
objMessage.Status = objConstants.MESSAGESTATUS_PENDING
objMessage.Recipient = "+0011234567890"
objMessage.Body = "Mobile SMS Test message"
obJMessageDB.Send(objMessage);
objMessageDB.Close