CAP is an XML standard that is used to send alert messages around between government agencies. There are a few sources of ATOM/CAP feeds out there from the Weather Service and USGS, so I have been experimenting with parsing these feeds with Drupal's FeedAPI. There is still much work to be done with handling some of the unique namespaces that show up in these feeds, but it is a start.

We have a demo site up at http://ic.metanomy.org

And I attached some alpha quality code. It's essentially the Common Syndication Parser hacked to work with CAP 1.1 - Just unzip it and put it in your FeeedAPI module folder. You can then enable it as a module and use it as a parser. This is experimental code so do not use it in a production environment. Hope to have it or something like it contributed to the FeedAPI project.