The full rssCloud walkthrough explains how to write a cloud server or a cloud-aware aggregator. Luckily it's much simpler to publish a cloud-aware feed, which is good because there are so many of them.
You're welcome to use my cloud server. If you do you can just copy the cloud element from my feed. But be aware that my server will go away someday. When that happens, you'll have to find another server. But hopefully by then there will be many to choose from.