Photoshop:
http://www.adobe.com/

http://www.adobeevangelists.com/   “Photoshop CS Fundamental Techniques”,“Photoshop CS Advanced Techniques”, and "Photoshop CS Extras" by Julianne Kost, available on DVD (http://www.software-cinema.com/) for $299/set of 3.

http://www.totaltraining.com/ “Total Training for Photoshop CS2 ”, hosted by Deke McClelland, on DVD are an excellent way to learn more about Photoshop and are worth the $300 cost.

NIH Image:

http://rsb.info.nih.gov/nih-image/

Email list:   listserv@list.nih.gov with text "subscribe nih-image yourfirstname yourlastname" to subscribe.

Scion Image:

http://www.scioncorp.com/               

Digital Cameras:

http://www.dpreview.com/

Hardcopy Stability Issues:

http://www.wilhelm-research.com/

Short Course & Workshop (Dr. John Russ):

Computer-Assisted Image Analysis and Measurement http://drjohnruss.com/

Image Processing Tool Kit CD-ROM http://www.reindeergraphics.com/