Sightwalk.de offer a similar service as Google Maps StreetView in Germany. Not too many images available yet, but there are some from Köln and Berlin. Google Maps StreetView is not yet available in Germany. Next couple of countries rumoured to be covered by StreetView is Canada and Denmark.
Quick update from Pascal at googlewatchblog.de:
http://sightwalk.de/ launched street images of Köln yesterday. Hamburg, Bonn, Munich, Berlin, Düsseldorf will follow soon.