If mtfs IsNot Nothing Then
  Dim rs As IRegistration = _
  DirectCast(mtfs.GetService(GetType(IRegistration)), IRegistration)

  Dim res() As RegistrationEntry = _
    rs.GetRegistrationEntries(String.Empty)

  Debug.WriteLine("Registration Entries and their Event Types.")
  For Each re As RegistrationEntry In res
    Debug.WriteLine(re.Type)
    If re.EventTypes.Length > 0 Then
      For Each et As EventType In re.EventTypes
        Debug.WriteLine("-->" & et.Name)
      Next
    Else
      Debug.WriteLine("-->No Events Found")
    End If
  Next
End If

Registration Entries and their Event Types.
Build
-->Build Completion Event
-->Build Completion Event 2
-->Build Status Changed Event
vstfs
-->BranchMovedEvent
-->NodeCreatedEvent
-->NodePropertiesChangedEvent
-->NodeRenamedEvent
-->NodesDeletedEvent
-->ProjectCreatedEvent
-->ProjectDeletedEvent
Reports
-->No Events Found
Wss
-->No Events Found
WorkItemTracking
-->No Events Found
VersionControl
-->CheckinEvent
TestTools
-->No Events Found

<SoapDocumentMethod( _
  "http://schemas.microsoft.com/TeamFoundation/2005" & _
  "/06/Services/Notification/03/Notify", _
  RequestNamespace:="http://schemas.microsoft.com" & _
  "/TeamFoundation/2005/06/Services/Notification/03")> _
  <WebMethod()> _
Public Sub Notify(ByVal eventXml As String, _ 
                 ByVal tfsIdentityXml As String)

End Sub

<SoapDocumentMethod( _
  "http://schemas.microsoft.com/TeamFoundation/2005/06" & _
  "/Services/Notification/03/Notify", _
  RequestNamespace:="http://schemas.microsoft.com/TeamFoundation/" & _
  "2005/06/Services/Notification/03")> _
<WebMethod()> _
Public Sub Notify(ByVal eventXml As String, _
  ByVal tfsIdentityXml As String)

  Const logSource As String = "MSDNMagTFSEvents"
  Const logApp As String = "ProcessEvents"
  Dim el As New EventLog(logApp)
  el.Source = logSource

  Try
    el.WriteEntry("Notify event called.")

    If eventXml Is Nothing OrElse eventXml = String.Empty Then
      el.WriteEntry("eventXml data is empty.")
      Return
    Else
      Dim x As XElement = XElement.Load(New StringReader(eventXml))
      Dim referenceName = (From element _
        In x...<ChangedFields>...<ReferenceName> _
        Where element.Value = "System.Title").SingleOrDefault
      If referenceName IsNot Nothing Then
        Dim oldValue = referenceName.Parent.<OldValue>.Value
        Dim newvalue = referenceName.Parent.<NewValue>.Value
        Dim refNameId = (From element _
          In x...<CoreFields>...<ReferenceName> _
          Where element.Value = "System.Id").SingleOrDefault

        ' the Work Item's ID is always included.
        Dim id = refNameId.Parent.<OldValue>.Value
        ' Do something with the data
        Dim sw As New StringWriter()

        sw.WriteLine("Work Item {0} was changed.", id)
        sw.WriteLine("Old Title: " & oldValue)
        sw.WriteLine("New Title: " & newvalue)

        el.WriteEntry(sw.ToString())
      Else
        ' The title wasn't changed. 
        ' Do something else
      End If
    End If

  Catch ex As Exception
    el.WriteEntry(ex.Message, EventLogEntryType.Error)
  End Try
End Sub

If mtfs IsNot Nothing Then
  UpdateStatus(stSubscribeforWebService, True)

  Dim es As IEventService = _
   DirectCast(mtfs.GetService(GetType(IEventService)), IEventService)

  Dim dp As New DeliveryPreference()
  dp.Address = String.Format("http://{0}{1}", mtfs.Uri.Authority, _
    "/MSDNMagTFSEvents/ProcessEvents.asmx")
  dp.Schedule = DeliverySchedule.Immediate
  dp.Type = DeliveryType.Soap

  Dim filter As String = Nothing
  If Me.chkOnlySelectedProject.Checked Then
    filter = String.Format("PortfolioProject = '{0}'", _
      Me.cboTeamProjects.SelectedItem.ToString())
  End If

  Try
    Dim subId As Integer = es.SubscribeEvent( _
      mtfs.AuthenticatedUserName, "WorkItemChangedEvent", filter, dp)

    MsgBox(String.Format(otSubscriptionAdded, subId), _
           MsgBoxStyle.Information, otSuccess)

    Me.btnListMySubs_Click(Me.btnListMySubs, EventArgs.Empty)
  Catch ex As Exception
    MsgBox(ex.Message, MsgBoxStyle.Critical, ex.Source)
  End Try

  UpdateStatus(stStatus, False)
End If