R help - Feb 2010 - Plot point text labels over polygon w/o overlap?

Using pointLabel in the maptools package will plot text labels for points to
avoid overlap of text.

But is there a way to avoid/minimize overlap of text labels with the outline of
an underlying polygon?

For example, when plotting location of cities, one would like the text labels to
not fall on top of nearby country/state borders, etc.

Many thanks,
Kevin Ummel

Central European University
Department of Environmental Science and Policy