You've downloaded Shazam and Pandora from the iTunes App Store so you can listen to heart-pumping tunes while you work out, but that's only the beginning of what the iPhone can do—there are well over 1,000 health and fitness-related applications in the App Store. Check out this list of useful iPhone and iPod Touch applications that can help kick up the tempo in your workouts.

What: Instant Butt Lift by SHAPE
When To Use: If you've ever arrived at the gym or laced up your sneakers and felt directionless, this is just the app you need. Consider it your own personal trainer, complete with seven different workouts focusing on your glutes, hips, and thighs with a combination of high-intensity cardio and strength training. This is the first in a series of apps developed by SHAPE.
Cost: $1.99