Android: One of the neatest features of Android is the ability to customise notifications to a high degree. LEDBlinker gives you even more power.
The app allows you to customise the colour and blink rate of your notification LED on a per-app basis, and even get notifications if your battery reaches less than 10 per cent or when it's fully charged. Unlike many other apps of its kind, this one does not require root. It does have a few bugs, however, so be sure to test thoroughly as you set it up.