Update README to reflect gRPC support.

Fixes #13.

README

@@ -23,8 +23,8 @@ protocol buffers; and a library that implements run-time support for
 encoding (marshaling), decoding (unmarshaling), and accessing protocol
 buffers.
 
-There is no support for RPC in Go using protocol buffers.  It may come
-once a standard RPC protocol develops for protobufs.
+There is support for gRPC in Go using protocol buffers.
+See the note at the bottom of this file for details.
 
 There are no insertion points in the plugin.
 
@@ -146,3 +146,13 @@ To create and play with a Test object from the example package,
 		}
 		// etc.
 	}
+
+
+gRPC Support
+============
+If a proto file specifies RPC services, protoc-gen-go can be instructed to
+generate code compatible with gRPC (http://www.grpc.io/). To do this, pass
+the `plugins` parameter to protoc-gen-go; the usual way is to insert it into
+the --go_out argument to protoc:
+
+	protoc --go_out=plugins=grpc:. *.proto