Download the library + demo’s at http://blog.aboutme.be/wp-content/uploads/ckeditor_flex_air/ckeditor_flex_air.zip

Again, some release notes (same as FCKEditor actually :-)):

When you extract the zip file, you will find an swc file, an assets folder and de demos folder. If you want to use CKEditor in your own Flex or AIR projects, add the swc to your library path, and the assets folder to your src folder (just like the demo projects).

When you use the component in a Flex project, you need to ensure you set the wmode property to ‘opaque’. Also, if you run it on your local filesystem with Internet Explorer, you won’t see the component. It works fine if you run it on a webserver.