I'd think it would depend on what platform you're using and what other than in-house WiFi is around. What hospital/area are you at? That might bring some ideas to mind for folks that are in that area.
I'd be fairly sure that there isn't yet a functional medical app for the iPhone, but maybe there's a Blackberry product that does what you want. Palm may be the default medical PDA, but isn't that because many schools require their students to use one standard piece of hardware? (That's the case around here...) I guess the issue comes down to how married you are to your iPhone/Touch.