Hi all, Thanks for the many (and quick!) responses!! Some others have asked me for what I find out, so here is the information:
ImageJ (http://rsb.info.nih.gov/ij/ ) is the program of choice by almost everyone (others have mentioned Scion).
Tim -- Tim Nuttle, PhD Assistant Professor, Ecology Department of Biology Indiana University of Pennsylvania 114 Weyandt Hall Indiana, PA 15705 http://nsm1.nsm.iup.edu/nuttle/