Earlier this month, the Privacy Commissioner of Canada released a set of guidelines for the use of video surveillance by law enforcement. The fourteen principles do not, however, bind any law enforcement agencies and nobody is required to follow them. See: OPC Guidelines for the Use of Video Surveillance of Public Places by Police and Law Enforcement Authorities (March 2006).
The Canadian IT Law Association blog has some discussion on the topic. Check it out here: IT.Can Blog - Police Monitoring of Public Spaces with Video Cameras: Privacy Commissioner and RCMP Guidelines.