Code Sample:

Imports System.Net
Imports System.IO
Dim client As WebClient = New WebClient
' Add a user agent header in case the requested URI contains a query.
client.Headers.Add("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)")
client.QueryString.Add("mobileID", "xxxx")
client.QueryString.Add("password", "xxxx")
client.QueryString.Add("to", "xxxx")
client.QueryString.Add("text", "This is an example message")
Dim baseurl As String = "http://api.aussiesms.com.au/?sendsms"
Dim data As Stream = client.OpenRead(baseurl)
Dim reader As StreamReader = New StreamReader(data)
Dim s As String = reader.ReadToEnd()
data.Close()
reader.Close()
Return