As a personal project, I wanted to put together a parser for VAST responses. So I created an ActionScript library on GitHub. It’s basic but takes care of the monotonous XML to AS3 mappings. It also allows for custom extension parsers.
For more info, visit the project page: http://nathanhinish.github.com/AS3-IABLib/
UPDATE: I think a WP update borked the page. If there’s interest I’ll put it up. Otherwise, here’s the link to the GitHub repo. https://github.com/nathanhinish/AS3-IABLib
UPDATE #2: There is growing interest in the library so I wanted to make sure the documentation is available online. To that end, I created a GitHub project page that has a link to the documentation. http://nathanhinish.github.com/AS3-IABLib/