If you ever had to look for stock footage for fireworks and couldn't find a good shot, this site has a great visual effects kit for generating fireworks and compositing the images in Final Cut Pro. There are 40 individual fireworks effects that can be composited and layered onto your footage to create an infinite number of custom fireworks sky scenes. And the great thing is all the effects are free.
http://royaltyfreestockvideofootage.com/rfvf_store/index.php?cPath=31_190
http://royaltyfreestockvideofootage.com/rfvf_store/index.php?cPath=31_190