I have recently created a webpage to assist plugin developers in creating and understanding how to create custom fireworks thanks to the ItemMeta system added by feildmaster It can be found at http://limebyte.github.com/FireworkGenerator/ and should be pretty easy to understand. It is still a work in progress so if you are a jQuery expert or someone who is extra stylish head over to https://github.com/limebyte/FireworkGenerator and make a pull request or make a suggestion.
