Dim doc As New XmlDocument()
doc.LoadXml("<?xml version=""1.0"" encoding=""utf-8""?><mainroot><root><record><id>1</id><nome> nome1 </nome><cognome> cognome1</cognome><piva> piva1 </piva></record><record><id>2</id><nome>nome2 </nome><cognome>cognome2 </cognome></record><record><id>3</id><nome>nome3 </nome><piva>piva3 </piva></record></root></mainroot>")

Dim oNodes As XmlNodeList = doc.SelectNodes("/mainroot/root/record")

For Each node As XmlNode In oNodes
  Dim id As XmlNode = node.SelectSingleNode("id")
  Dim nome As XmlNode = node.SelectSingleNode("nome")
  Dim cognome As XmlNode = node.SelectSingleNode("cognome")
  Dim piva As XmlNode = node.SelectSingleNode("piva")

  If id IsNot Nothing Then
    MessageBox.Show([String].Format("ID = {0}", id.InnerText))
  End If

  If nome IsNot Nothing Then
    MessageBox.Show([String].Format("NOME = {0}", nome.InnerText))
  End If

  If cognome IsNot Nothing Then
    MessageBox.Show([String].Format("COGNOME = {0}", cognome.InnerText))
  End If

  If piva IsNot Nothing Then
    MessageBox.Show([String].Format("PARTITA IVA = {0}", piva.InnerText))
  End If
Next