Just a few things:
1. Black powder is not gun powder. The brits call them the same thing, but here in america, black powder refers to the tri-component mix based on saltpeter, and gunpowder refers to smokless powder.
2. Most salutes (the exploding fireworks) don't contain black powder. They contain flash, a completely different mixture all together. None that I know of use smokless.
As for your own black powder, I don't think that this group is really meant to discuss how to make it or where to get chemicals; if you want to ask other questions related to properties, history, etc., then it's OK, but the rest probably won't be answered. Now, if you're into your own amateur fireworks, etc., then the place to go is the usenet newsgroup rec.pyrotechnics. Many of the people there make their own black powder. But don't just take their word off of usenet how to do it. Ask the people there for references, actual print books that talk about how to do exactly what you're asking for. I know for a fact that these books are out there and reliable because I own several of them. If you're making BP for your own fireworks, just make sure you're being safe and legal about it. Making fireworks in a state without an amateur exemption is asking for it.
In case you don't know where to find rec.pyrotechnics, go to google, click on the 'groups' tab, then skim down to the rec.pyrotechnics group. Search through their archives or post a new thread.