The PALM project aims to implement a dynamic MPMD coupler for parallel codes. It has originally been designed for oceanographic data assimilation algorithms, but its application domain extends to every kind of parallel dynamic coupling. The main features of PALM are the dynamic launching of the coupled components, the full independence of the components from the application algorithm, the parallel data exchanges with redistribution and the separation of the physics from the algebraic manipulations performed by the coupler. A fully operational SPMD prototype of the PALM coupler has been implemented and it is now available for research purposes.