近々使うことになるかもしれないのでメモ。

Public Class Singleton
    Private Shared ReadOnly mInstance As New Singleton

    Public Shared Function GetInstance() As Singleton

        Return mInstance

    End Function

    Private Sub New()
    End Sub
End Class

参考元はこちら
http://msdn.microsoft.com/ja-jp/library/ms998558.aspx
http://www.atmarkit.co.jp/fjava/javatips/075java007.html