Label corners of map extent with X,Y or Lat/Lon coordinates

Discussion created by SaultDon on Mar 18, 2011
From the image below, you can label a maps corners based on an existing Measure Grid, but this label indicates not the corner position, but the grid line closest to that edge.

Using either a Measured Grid(in X,Y) or a Graticule (lat,lon / dd / dms) what are some of the options in ArcGIS 9 and above that would allow you to do this easily or automatically?

My current workflow:
Create extent polygon > Convert to points > Create two new x/y fields and calculate geometry > use those fields in a label expression > optional - copy and paste to graphic element

The question is also being asked on stackexchange: Labeling coordinate value at 4 corners of graticule in arcgis