To use bulk SMS API from various providers Try following...
I am using the same....
www.freesmsapi.org[
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Dim sURL As String
Dim objReader As StreamReader
sURL = "http://www.freesmsapi.org/sms.php?provider=site2sms&uid=XXXXXXXXXX&pwd=password&phone=" & lstsmsph.Items.Item(i) & "&msg=" & txtsmstext.Text
Dim sResponse As WebRequest
sResponse = WebRequest.Create(sURL)
Dim objStream As Stream
objStream = sResponse.GetResponse.GetResponseStream()
objReader = New StreamReader(objStream)