Have you thought about running a half marathon but got discouraged because you did not know how to train? You should try the Runkeeper app.
It is free to download and to use. Basically this app keeps track of your runs and tracks your pace and time.
Plus the app includes several different training plans to meet your fitness goals. For example, if you want to run a half marathon, go to the “my plan” section of the app and go under “training plan” and choose which plan works best for you.
It works on both iPhone and Droids.