Cap_parser is a project mainly written in ..., it's free.
Common Alerting Protocol parser for Drupal 6 FeedAPI
Unless otherwise noted everything in here is GPL
This is an experimental Common Alerting Protocol(CAP) Parser
It's for use with Drupal 6 and the FeedAPI module
It is essentially a copy of the common syndication parser that comes with FeedAPI tweaked to work with ATOM/CAP feeds.
It's very rough but works for basic needs.