P2P Cities
This project page aims to bring together a directory of projects related to cities worldwide.
Australia
Melbourne's Future Melbourne Project - employing a wiki for unrestricted editing (during public consultation windows) on the city's ten year plan
URL = http://www.futuremelbourne.com.au/wiki
New Zealand
NZ Police Act Review wiki (ended in 2007)
URL = http://wiki.policeact.govt.nz/
U.S.A.
City of Afton, Minnesota is employing a wiki for their planning process (current)