Take a deep breath. Now take another. That's the idea behind HeartMath Inner Balance. This accessory for iPad, iPhone and iPod touch helps you synchronize your breathing and steady your heart rhythm, all while focusing on positive emotions. The goal: to enter a state of "psychophysiological coherence." That is, you won't just be calm and content, but focused, too. Find out if $99 is too much to pay for mental discipline.