The Arlington Wiki is administered by David Meyers (dmeyers). A whole host of volunteers add and maintain the information on it.
The Arlington Wiki is hosted by http://www.wikidot.com and runs their wiki software.
For questions about Arlington which you haven't found an answer to here, your best bet may be to subscribe to the Arlington List and ask there - or search the list's archives.
For questions about the wiki itself, please take a look at WikiDot's page and documentation, or feel free to contact dmeyers through his profile here.