With all of the apps and mobile devices being developed out there it is inherent that there will be more and more regulation. One piece of regulation that already exists, and must be complied with is HIPAA. Not being the expert on the issue, I will direct you to someone who obviously has more experience. Adam H. Greene wrote a great article for mobihealthnews.com that can be found here.
I really am not in a position to add or take away from what he wrote due to my complete lack of experience compared to him so I will leave it at that. I highly encourage anyone who is trying to be successful in this market to take a few minutes and take advantage of his expertise.