software for densitometry using a scanner?

[David W. Mullins]

Does anyone know of a software package, either for Mac or IBM, that will 
allow one to scan an image--for example, a photograph of an ethidium stained 
gel--and then perform densitometry calculations?  I would like to have a 
quantitative assessment of RT-PCR product, using the equipment I have at hand.

Any suggestions--software or alternative methods that have worked well for 
you--will be greatly appreciated.

Many thanks,
David W. Mullins, Ph.D. Student
Department of Biology, Microbiology and Immunology Section
Virginia Polytechnic Institute and State University (Virginia Tech)
Blacksburg, VA  24061-0406
Lab     (540) 231-8933
Fax     (540) 231-9307