Web service will be platform independent and language independent. If a web service is developed by using JAX-RPC, can I develop a JAX-WS client to invoke JAX-RPC?
If you can use .Net client to invoke JAX-RPC, JAX-WS client should be much easier. And it actually is. Use the WSDL exposed by your JAX-RPC service to generate a JAX-WS client. Let us know if you run into any specific issues.