On-camera flash is usually a terrible idea (with just two – maybe three – exceptions I can think of). It lights up your subject, sure, but it totally kills the mood that made you want to take a photo in the dark in the first place.
But if you’re a fan of shiny, overexposed faces, red eyes and disappearing backgrounds then why not grab an iblazr, the world’s first all-lower-case iPhone flash. Kidding. It is all lower cae, but that’s not really its tagline. It’s real tagline is “is the first universal LED flash for smartphones and tablets.”
Lame.