The Wireless Leiden Foundation has established an open, inexpensive, fast wireless network for Leiden and surrounding villages. It is an independent network, which technically links up seamlessly to the Internet, but can also be used for free local communication within the Leiden region. Wireless Leiden is a non-profit organisation, operating completely with professional volunteers and aiming at infrastructure and not services. All our software, technological and organisational knowledge is freely available to others under an open source license.