A little late but would this be what you are after?

  Private Sub DataGridView1_CellValidating(ByVal sender As Object, ByVal e
As System.Windows.Forms.DataGridViewCellValidatingEventArgs) Handles
DataGridView1.CellValidating
     Dim CurrentCell As DataGridViewCell =
DataGridView1.Item(e.ColumnIndex, e.RowIndex)

     If CurrentCell.IsInEditMode Then
        Dim GridControl As Control = DataGridView1.EditingControl
        Console.WriteLine("------------------------------------")
        Console.WriteLine("Edited value ""{0}"" Former value ""{1}""",
GridControl.Text, DataGridView1.Item(e.ColumnIndex,
e.RowIndex).Value.ToString)
        Console.WriteLine("------------------------------------")
     End If
  End Sub