Here’s a nice 4 minute demo of 10 different iPhone medical applications from Nature Video. Two coolest:
iCut DNA lets you search the Restriction Enzyme Database (REBASE) for enzymes and the DNA nucleotide sequences they cleave.
Thinklabs Digital Stethoscope is a somewhat pricey app that allows you to listen and record heart beats on your iPhone. Caution: remixing patients auscultations into your next dj set may constitute a HIPAA violation.