Found it!
Private Sub GridGroupingControl1_RecordValueChanging(sender As Object, e As RecordValueChangingEventArgs) Handles GridGroupingControl1.RecordValueChanging
Dim NewValue As VariantType = e.NewValue.ToString
Dim ColumnName As String = e.Column
Dim Oldvalue As VariantType = e.Record.GetValue(ColumnName).ToString
Dim TableName As String = GlobalVariables.CurrentTable
Dim CurUser As String = GlobalVariables.CurrentUserAbbrev
End Sub