interactive 2-D plot interrogation

Greetings Friends:

I am trying to find a widget or some other method to let me interrogate a 
2-D image using the mouse.  I have a data.frame that I can visualize using
image() in R.  I would like to point to a pixel and have its coordinates
displayed.

I've read Peter Dalgaard's primer on R-Tcl/Tk, R-News, 1(3):27-31, and his
update R-News2(3):25-27, but am still struggling. 

Can anyone suggest a method for interactively interrogating of a 2-D image?

Many thanks.

Charles Annis, P.E.
 
Charles.Annis at StatisticalEngineering.com
phone: 561-352-9699
eFax:  503-217-4849
http://www.StatisticalEngineering.com