llenado de DropDownList

¿Como puedo poner en blanco la primera seleccion de mi dropdownlist?

Algo asi como:
-Nada-
Y que al desplegar el dropdownlist me muestre todos los demas registros

El llenado de mi dropdownlist lo hago de la sig manera:

Sub Page_Load(Sender As Object, E As EventArgs)
If Not Page.IsPostBack Then
DropDownList1.DataTextField = "TipoCont"
DropDownList1.DataSource = TiposDeContactos()
DropDownList1.DataBind()
End If
End Sub

Function TiposDeContactos() As System.Data.DataSet
Dim connectionString As String > "Provider=Microsoft.Jet.OLEDB.4.0; Ole DB Services=-4; Data
Source=C:\Inetpub\wwwr"& _
"oot\ContactosASP\contactos.mdb"
Dim dbConnection As System.Data.IDbConnection = New
System.Data.OleDb.OleDbConnection(connectionString)

Dim queryString As String = "SELECT
[TiposDeContacto].[TipoCont] FROM [TiposDeContacto]"
Dim dbCommand As System.Data.IDbCommand = New
System.Data.OleDb.OleDbCommand
dbCommand.CommandText = queryString
dbCommand.Connection = dbConnection

Dim dataAdapter As System.Data.IDbDataAdapter = New
System.Data.OleDb.OleDbDataAdapter
dataAdapter.SelectCommand = dbCommand
Dim dataSet As System.Data.DataSet = New System.Data.DataSet
dataAdapter.Fill(dataSet)
Return dataSet
End Function

Saludos desde México y Gracias por leer mi post.
Enrique Rodríguez