If you have kids, you'll eventually need an app like this.
Wesley Kids is the creation of Wesley Medical Center in Wichita, Kan. It's a great "all-in-one" iPhone app that combines a super useful (and very deep) symptom checker with a family medication tracker. There is also parental advice on issues from "ADHD" to "whining."
Don't have an iPhone? Bookmark the website — it contains all of the symptom tracker content.