While at Macworld I got to see a great demo of 3-D anatomy and phsyiology apps on the iPad. These apps are perfect for students, for doctors who need to explain something particular to a patient and want to graphically illustrate the situation, and for people who are simply curious about the human body. 3D4Medical has a total of 25 apps, including both free and paid. They range from the skeletal system to the cardiovascular system to the muscle system, with the price ranging from $15-22 on the iPad and less than $10 on the iPhone.
One really neat feature is the way the apps let you add or strip away layers. The video, for example, first shows a knee joint but then during the demo you can see how it can be overlain with a 3-D image that of cartilage and tendons.
Here's another good demo.