"Work It, Girl!"
This app has a short, looped video clip to go with each exercise, to show you exactly how to do it. You can set reminders at different times for each day. There's no tutorial however, so using the app is a little confusing at first. Also, you can't skip exercises - so no cheating!
The video clips are a very nice feature, as is being able to set notifications at different times for each day of the week, giving you the ability to match your workouts to your weekly schedule.
There's no tutorial for using the app, so a little bit of experimentation is required when you first start using it. There's also no way to skip exercises, a feature that most workout apps do and should have. But then, I guess that means you can't cheat...?