Since 2006 or so I used a set of scripts Daniel Robillard made for iView 3x (he posted in their forums in the good old days). It includes something called "Transfer Annotations", which can move/copy entries from just about any iptc field to another. The scripts are in French, so that took me a few minutes to figure out. They somehow work in ExpressionMedia, too (for me anyway).http://iview.free.fr/scripts_iview.html
Look for "Transfert d'Annotations | Annotations Transfer" about a quarter of the way down.