Select the path layer from the path palette, select the layer in the layers pallet. Then create a vector mask: Menu->Layers->Vector Mask->Current Path. This will add a vector mask to the layer which be default will work as a clipping path and be linked to the the layer.
If you want the path with the layer but don't want a clipping path you could also turn it into a fill layer: select the path, Layer->New Fill Layer->Solid Color. This will get the path on the layers palette where it can be linked and moved with other layers.