This software cropps up in conversation on these forums from time to time. It's a stand alone particle generator to generate clip that you can then composit into your own creations. Literally thousands of library emitters out of the box.
Anyway, Digital juice are doing a special at the moment. It's half price.
Pop over to wondertouch: home of particleIllusion to check out the product and then buy it cheap at Particle Illusion 3.0 :: Digital Juice
I am not affilliated to either company. I've been using particleIllusion for a few years and love it. Got an email flyer from Digital Juice today so thought I would pass on the link.