So check this site out. Great resource on what is actually useful in terms of medical apps for the iPhone. This is a Must have resource if you are scheming iPad apps for hospitals or physician's ;)
One example of an app they reviewed is iRadiology. This is an app that has over 500 radiology cases. The cases are sourced from a Harvard Med professor Dr. Leiberman . This is a hand picked app, by healthcare professionals, for being a resource which is actually useful.