Friedel Völker has started an impressive list of place and regional wikis in a new XING Group European Regiowiki Society.
Until now most wikis on this list are from Germany, but he plans to aggregates Regiowikis from all over Europe and had already some success as you can see ... (please add your wiki!)
Andere Listen / Wikis
Liste Stadtwikis (Schwerpunkt Deutschland)
Liste at city-wiki-center (International)
You find our last Update on Placeblogs here