Proxy your api calls for flash
Many sites use flash heavily and also want to make use of ajax like functionality. Sometimes you need to make a call to a third party service such as twitter, youtube, tinyurl, etc. There is a problem that comes up when you try to have flash interface directly to these third parties, there are security measures in place for cross site access to try and keep you safe. If you can't call this third party service directly from flash, there is an alternative, proxy the service through an api on your server.
Flash can call a php page from your server, which in turn calls a remote api and returns the result back to flash. For example, recently we created a microsite that provides a link back to the current state using a tinyurl so the user can post this in twitter. The flash interface does not call tinyurl directly, it calls a php script hosted on the same domain and asks for the url to be run through tinyurl. The php script makes the api call to tinyurl and then returns it wrapped in xml to the flash which in turn displays it to the user.