An excellent article on the new OpenSearch technology from A9 can be found on Last-child.com, along with a full explanatoin of what the technology is, and how it can be used. I look forward to playing with it more in the future, and will post more on that when I have.
~Nicole
You are right that OpenSearch is a great new technology. Check out OpenSearch Search plugins for IE7 and Firefoxwhich has hundreds of the discovery files for OpenSearch. It’s also easy to add your own.