We present KikuNavi, a real-time pedestrian navigation system as a social networking service operating on a mobile phone. A user who becomes lost can use our system to easily find someone (the navigator) who knows how to reach the user's destination. The navigator can sketch the route, which appears on the lost user's mobile phone. The navigator can also choose to lead the user; the lost user's phone displays an arrow pointing toward the navigator. Most existing navigation systems rely on digital maps and GPS geospatial information, but our system is based on the fact that we often become lost in situations when the combination of digital maps and GPS does not work well. Our concept is to support pedestrian navigation even in such an environment by relying on the collective intelligence of people nearby, connected by mobile phones.