Using mobile technologies for healthcare is not just for self-diagnosis or as an alternative to expensive medical care. Many doctors and hospitals are adopting the technology and encouraging their patients to adopt it. There are lots of things you can do smaller and cheaper where telehealth systems or healthcare websites are currently being used. Preventive medicine mobile applications have been successful for improving health outcomes for patients with chronic conditions, in particular. Read the article before casually dismissing the field as a bunch of hypochondriacs trying to self-medicate.
If you're a developer interested in the mobile health field, the mHealth Summit is currently the best annual conference.focused specifically on mobile health out there: http://www.mhealthsummit.org/
Eric Topol, the subject of the NY Times article in the summary above, was one of the keynote speakers at the 2011 conference, along with HHS Secretary Kathleen Sebelius, Surgeon General Regina Benjamin, and FCC Chairman Julius Genachowski.