You can easily track the changes in the columns order using RadGridView.ColumnReordered event.
In 2009.Q2 version there is a ColumnWidthChanged event, but this event supports columns layout infrastructure and should not be used directly from your code. That's why this event is obsolete with the current release (2009.Q3), which means that with the next official this event will be no longer available. Can you provide us with more detailed information about your scenario how do you intend to use this event? We need this information to reconsider adding such public API.
Thank you in advance.
the Telerik team