i've developed a system. should be out "real soon now". but if you want something that's been out for a while, and has been shaken down pretty well, try leanp

i've developed a system. should be out "real soon now". but if you want something that's been out for a while, and has been shaken down pretty well, try leanpub.com. there's also pressbooks.com, and penflip.com, and more. -bowerbird