Imposm is an importer for OpenStreetMap data. It reads XML and PBF files and can import the data into PostgreSQL/PostGIS databases.
It is designed to create databases that are optimized for rendering/WMS services.
It is developed and supported by Omniscale, runs on Linux or Mac OS X and is released as open source under the Apache Software License 2.0.
See http://imposm.org/ for more information.