As FITC came and went at the end of April, the original developer for PureMVC Cliff Hall could not make it (sprained ankle), but Tim Willison covered for him. He posted some slides at his blog in regards to PureMVC development. He provides an example done in Flash. (I assume it to be in Flash CS4. Most examples are done in Flex. So this is a treat!)
Here are the links:
FITC: http://www.oddlystudios.com/?page_id=192&paged=3
Example, Part 1, 2, 3: http://www.oddlystudios.com/?page_id=192&paged=2
Part 4, 5, 6: http://www.oddlystudios.com/?page_id=192
DJ