The Reference Manual and User Guide is published on the UrbanSim website in both pdf and html form. To avoid serving as a spam magnet, please don't put real email addresses in the html version - instead use circumlocutions of some sort, e.g.
info (at) urbansim.org
If you want to be fastidious, you can put a real email address in the pdf version though by using the latexonly and htmlonly macros -- there is an example of doing this near the end of Chapter 1 (the introduction), or search the latex source for (at).