Someone posted answer recommending the OpenEMR project, but now I can't see it anymore. Maybe they decided to delete it for some reason? Anyway, I think the project's aims are commendable:

OpenEMR is the most popular open source electronic health records and medical practice management solution. ONC certified with international usage, OpenEMR's goal is a superior alternative to its proprietary counterparts. With passionate volunteers and contributors dedicated to guarding OpenEMR's status as a free, open source software solution for medical practices with a commitment to openness, kindness and cooperation.

http://open-emr.org/