It comes with a demo which allows you to adjust various settings and see the results in realtime.
Source is included both for the particle system and for the demo.
The textures tile seamlessly and obvious repeating patterns have been kept to a minimum. By royalty-free, we mean that you can use these in any form of art, commercial or otherwise in any medium and sell that art. What you can't do with the textures is sell them or give them away to others. By default CD's will be shipped thorugh US mail in a padded diskette mailer. If your business has a FED EX account, we can apply the shiping costs to that instead if you provide us with the number.