I am starting with the standard 3.1.1 ZeroMQ library and making a packaged version for the iPhone/iPad/iPod Touch. Why you might ask? Because it's there? No, because having a high performance messaging engine attached to a whole bunch of devices in the field that are almost always connected creates some fascinating possibilities.
READ THIS There is an issue LIBZMQ-270(http://zeromq.jira.com/browse/LIBZMQ-270) which may be causing the pub sub test to fail. I can reproduce the problem using simple C++ programs executing PUB/SUB behavior. One of my tests (which weren't fantastic to begin with) are not working. Be advised.