I realize this is useful for cpu-bound computations; but for network-bound here is a REAL two-liner that will instantly make your program concurrent (not parallel):
from gevent import monkey
monkey.patch_all()
This is a lot lighter than processes. You can combine the two- use gevent to handle network, and then multiprocessing to handle cpu stuff!
I've used gevent in multiprocess situations, and it worked just fine. I did rig up my own gevent-based IPC, though. Just create a socketpair before forking, and attach some JSON-RPC (or protobuf/msgpack/etc) endpoints after.
You don't want multiprocessing to fork your process after gevent is loaded. If you can avoid that (like hold off on monkey patching) then it works great.
