Five interferometers in the world are going to produce scientific data before 2004 (VIRGO and GEO in Europe, the two LIGO interferometers in the US and TAMA in Japan). An Australian interferometer is under project while Japan is planning the construction of a second generation cryogenic interferometer.
A total of 5 resonant detectors, of which 3 in Europe, are in operation.
LISA, an ESA-NASA interferometer in space, is to be launched at the end of the decade and will be particularly sensitive to very low

frequencies which are out of reach from the ground because of the environment noise and of the limited baseline.

Close collaboration between the groups involved is taking place through regular meetings, exchange of data and common data analysis in view of setting up a world wide network of detectors.

A world wide coordination body (Gravitational Waves International Committee) ensures the high level coordination.