Quartz Particle Designer is the ultimate app to design particle effects like fireworks, flame, snow, etc.
Design your own effect, see changes in real time, copy & paste iOS or Mac code to your own project. App comes with a few samples to get you started.
Note: Particle effects are based on CAEmitterLayer and CAEmitterCell classes which are available on Mac 10.6+ and iOS 5.0+
Hint: hover over a field to get instant help.