A fair number of people have asked me for a reading list on the topic of online cities, so here is my Delicious Library generated list of related non-fiction which I've kept around. This doesn't include any texts on the technical underpinnings or political form of online cities, but it's a good starting place for understanding what cities are now and can be in the future.
People who know more than I do should feel free to chime in with suggestions.
Arquilla, John. Networks and Netwars: The Future of Terror, Crime, and Militancy. RAND Corporation, 2002.
Bacon, Edmund N. Design of Cities: Revised Edition (Penguin Books). Penguin (Non-Classics), 1976.
Beth Simone Balkin Jack M. Noveck. The State of Play. New York Univ Pr, 2006.
Balsamo, Anne. Technologies of the Gendered Body: Reading Cyborg Women. Duke University Press, 1995.
Bartle, Richard. Designing Virtual Worlds. New Riders Games, 2003.
Bollens, John C., and Henry J. Schmandt. Metropolis: Its People, Politics and Economic Life. Harpercollins College Div, 1981.
Boyd, S. Gregory, and Brian Green. Business & Legal Primer for Game Development. Charles River Media, 2006.
Caillois, Roger. Man, Play and Games. University of Illinois Press, 2001.
Calvino, Italo. Invisible Cities. Harvest Books, 1978.
Castronova, Edward. Synthetic Worlds: The Business and Culture of Online Games. University Of Chicago Press, 2006.
Chudacoff, Howard P., and Judith E. Smith. Evolution of American Urban Society, The. Prentice Hall, 2004.
Crawford, J. H. Carfree Cities. International Books, 2002.
Fujita, Masahisa, Paul Krugman, and Anthony J. Venables. The Spatial Economy: Cities, Regions, and International Trade. The MIT Press, 2001.
Gelernter, David. Mirror Worlds: or the Day Software Puts the Universe in a Shoebox...How It Will Happen and What It Will Mean. Oxford University Press, USA, 1993.
Glazer, Nathan. From a Cause to a Style: Modernist Architecture's Encounter with the American City. Princeton University Press, 2007.
Hall, Peter. Cities of Tomorrow: An Intellectual History of Urban Planning and Design in the Twentieth Century. Blackwell Publishing, Incorporated, 2002.
Horan, Thomas A. Digital Places: Building Our City of Bits. Urban Land Institute, 2000.
Huizinga, Johan. Homo Ludens. Beacon Press, 1971.
Jacobs, Jane. The Death and Life of Great American Cities. Vintage, 1992.
Jacobs, Jane. The Economy of Cities. Vintage, 1970.
Jacobs, Jane. Systems of Survival: A Dialogue on the Moral Foundations of Commerce and Politics. Vintage, 1994.
Kotkin, Joel. The City: A Global History. Modern Library, 2006.
Lessig, Lawrence. Code and Other Laws of Cyberspace. Basic Books, 2000.
Levy, Matthys, and Mario Salvadori. Why Buildings Fall Down: How Structures Fail. W. W. Norton & Company, 1994.
Lynch, Kevin. The Image of the City. The MIT Press, 1960.
Mccloud, Scott. Understanding Comics: The Invisible Art. Harper Paperbacks, 1994.
Mitchell, William J. City of Bits: Space, Place, and the Infobahn. The MIT Press, 1996.
Mulligan, Jessica, and Bridgette Patrovsky. Developing Online Games: An Insider's Guide. New Riders Games, 2003.
Mumford, Lewis. The City in History: Its Origins, Its Transformations, and Its Prospects. Harvest Books, 1968.
Putnam, Robert D. Bowling Alone : The Collapse and Revival of American Community. Simon & Schuster, 2001.
Reader, John. Cities. Grove Press, 2006.
Rheingold, Howard. Smart Mobs: The Next Social Revolution. Basic Books, 2003.
Rollings, Andrew, and Ernest Adams. Andrew Rollings and Ernest Adams on Game Design. New Riders Games, 2003.
Rollings, Andrew, and David Morris. Game Architecture and Design: A New Edition. New Riders Games, 2003.
Salen, Katie, and Eric Zimmerman. Rules of Play: Game Design Fundamentals. The MIT Press, 2003.
Sassen, Saskia. Global Networks, Linked Cities. Routledge, 2002.
Sterling, Bruce. Shaping Things. The MIT Press, 2005.
Tufte, Edward R. The Visual Display of Quantitative Information, 2nd edition. Graphics Press, 2001.
Tufte, Edward R. Visual Explanations: Images and Quantities, Evidence and Narrative. Graphics Press, 1997.
Wardrip-Fruin, Noah, and Nick Montfort. The New Media Reader. The MIT Press, 2003.
Whyte, William H. The Social Life of Small Urban Spaces. Project for Public Spaces Inc, 2001.