Why would you want to *make* saltpeter? It's one of the most common substances known to man. It's readily available for $5 a pound or less. The only reason I can think of to do it would be to remove the paper-trail (terrorism, anybody?), since I doubt "distilling" rotting wood and rain water (or whatever you're talking about) would be cool or entertaining in any way. In other words, since it can't be the means that interest you, it must be the ends.
Please, if you want dangerous, useless, and stupid terrorist info, look in the anarchist's cookbook or something. How do I know you shouldn't be messing around with this stuff? Because all the people here who know what they're doing use proper spelling, punctuation (not a single comma or period, in either post!), and grammar.
Please Mitch, lets get rid of this string and start talking about more serious stuff, like nuclear batteries or something.