Gym Hero is a great app for planning and logging your workouts. It has lists of various exercises depending on the muscle group they work out. For each exercise they highlight which muscles they are working out. They also have the recommended sets to do for each workout.
Download the Nike+ Training App. This app has hundreds of workouts from resistance exercises to cardio exercises. It also has audio and video with in depth explanations on how to perform each exercise. There are also ways to set up plans have a very detailed workout plan for a day to day or week to week basis.
Total Fitness is a fitness app with a focus on strength exercises. It has a large amount of strength exercises that you can view with images on how to perform each activity. It also has many other features such as calculators and others.