Your smartphone's LED flash is better than nothing if you find yourself needing to take a photo in the dark. But the results are usually harsh and uneven. So if you find yourself in need of better lowlight shots but refuse to buy a real camera, the Pocket Spotlight is a reasonable compromise.
It's basically a bank of 32 diffused LEDs that will provide soft, even illumination for up to an hour on a full charge. For smartphone users, it includes a mount for attaching it to a headphone jack, but it's also compatible with more traditional camera hotshoes as well.
Discerning mobile photographers probably won't mind dropping $US30 on the Pocket Spotlight since it can genuinely improve your shots, but as far as accessories go, it's a little on the bulky side, not to mention you'll have to awkwardly mount it under the iPhone 5 given the location of its headphone jack.