This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
We have implemented a distributed processing system using JMS (inter-jvm work with optional synchronicity, time-outs, error handling, etc.). It is quite complex and wasn't easy, but it works reasonably well. Some clustering technologies like Terracotta offer similar capabilities, but have their own pains to bear.
I don't think your use case is quite as demanding as ours, so jms might well be a good solution for you. The other possibility you may want to consider is using a lightweight web service like REST.