io ho fatto qualcosa così...
Dim strContent As String = ""
Dim objSR As StreamReader
Dim objResponse As WebResponse
Dim objRequest As WebRequest = HttpWebRequest.Create(VARIABILE_SITOWEB)
Try
objResponse = objRequest.GetResponse()
Dim x As Integer = 0
objSR = New StreamReader(objResponse.GetResponseStream(), System.Text.Encoding.ASCII)
strContent = objSR.ReadToEnd()
objSR.Close()
objResponse.Close()
MSG_SITO_RAGGIUNGIBILE
Catch ex As Exception
MSG_SITO_NON_RAGGIUNGIBILE
End Try
forse però ci son modi migliori ;)