Whenever you attach an iOS device to a power source to charge your battery, you receive feedback letting you know that the power connection succeeded. iPads and iPod touches provide audible feedback, but iPhones can provide both audible and vibratory feedback.
While these types of feedback can be useful in several scenarios, everyone knows that two sides exist to every story. With that in mind, PowerLess is a new free jailbreak tweak by iOS developer CydiaGeek that disables all power connection feedback entirely.