REBUS is the Resource, Balance and Usage website for the whole of WLCG, including topology information, resource pledges, and installed capacities.
MyOSG is web-site that provides a single place for most things related to the OSG including topology information, resource/service availablity/reliability information, current resource status, accounting information, etc.
GOCDB is the official repository for storing and presenting EGI topology and resources information.