The International Real-time Magnetic Observatory Network is a global network of observatories, monitoring the Earth's magnetic field. At this site, you can find data and information from geomagnetic observatories around the world.
International Monitor for Auroral Geomagnetic Effects (IMAGE)
The International Monitor for Auroral Geomagnetic Effects (IMAGE) consists of 41 magnetometer stations maintained by 8 institutes from Finland, Germany, Norway, Poland, Russia and Sweden. IMAGE studies auroral electrojets and moving two-dimensional current systems.
International Service of Geomagnetic Indices (ISGI)
The International Service for Geomagnetic Indices (ISGI) give its users access to historical geomagnetic indices.
World Data Centre for Geomagnetism (Edinburgh)
The World Data Centre for Geomagnetism (WDC) has a comprehensive set of digital geomagnetic data as well as indices of geomagnetic activity supplied from a worldwide network of magnetic observatories.