Skyscape RxDrugs for Android is a nice free medical app for those of you who are using an Android smartphone. You'll need to register for a free Skyscape account, but then you'll have a nice medical app on your Android smartphone.
Skyscape also offers Outline in Clinical Medicine (full edition) for free as well. Plus, Archimedes Medical Calculator is another free app that will come in handy in the clinical setting. If you're a medical student or resident, you'll want to have these free Skyscape apps on your smartphone.