Most CD's are designed to give you a vast number of images and to serve as an adjunct to your course and books. Wheater's is a solid book with a color new edition (latest edition) that comes with a CD. That should suffice for medical school. If you are getting to residency level then something like Histology for Pathologists (I think that is the name) is a very quick and to the point text.
Webpath and histo programs are awesome. However, as a pathologist you will be looking at H/E stained slides. Most CD-Roms or books use the best representation of a particular disease for categorizing and teaching. In general a pathologist learns by countless hours of seeing slides and developing pattern recognition skills. These become ingrained over time and become (for lack of a better word seemingly innate.) Again your best bet will be to do an anatomical pathology rotation and signing out daily at a multiheaded scope with attendings and residents. This is absolutely essential to get a feel for what histology becomes to a pathologist and not a medical student. I am an absolute believer in experiencing the field as it is. Not renditions of it on CDROM or in textbooks. However, if you are really looking for those resources what has been mentioned in the above posts is wonderful.