Imports System.IO
Imports System.Net

Public Class Form1
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim URL As String = ""
        URL = "username=" & TextBox1.Text & "&password=" & TextBox2.Text & "&mobile=" & TextBox3.Text & "&message=" & RichTextBox1.Text
        Dim client As WebClient = New WebClient()
        Dim data As Stream = client.OpenRead("http://api.twsms.com/json/sms_send.php?" & URL)
        Dim reader As StreamReader = New StreamReader(data)
        Dim resp As String = reader.ReadToEnd()
        MessageBox.Show("oe:" & vbCrLf & resp)
    End Sub
End Class