This app provides information on thousands of prescription medications and hundreds of over-the-counter drugs, as well as other capabilities, such as medical calculators. It's one of the most widely used medical apps; almost every doctor has it. It's available for the iPhone, BlackBerry, Android, Palm, and Windows Mobile. Epocrates RX is a basic free version. Souped-up versions start at $99 per year. Epocrates Essentials Deluxe at $199 per year provides evidence-based treatment information, treatment guidelines, lab preparation and interpretations, a medical dictionary, and ICD-9 and CPT codes. You typically start with a search, say for skin conditions like melanoma, where you can look at pictures, get etiology about the condition and information about related conditions, and then you can drill deeper and get even more information on those conditions. It also provides guidance on what to look for in terms of patient history, what tests to order, and treatment options for every size, shape, and type of patient.