For mobile robots and position-based services, localization is the most fundamental capability while path-planning is an important application based on that. A novel localization and path-planning solution based on a low-cost Visible Light Communication (VLC) system for indoor environments is proposed in this paper. A number of modulated LED lights are used as beacons to aid indoor localization additional to illumination. A Gaussian Process (GP) is used to model the intensity distributions of the light sources. Path-planning is hereby feasible by using the GP variance field, rather than using a metric map. Graph-based path-planners are introduced to cope with the practical situations. We demonstrate our path-planning system by real-time experiments performed on a tablet PC in an indoor environment.