I have never even heard of FLEX until today. Im not sure why you would need such an app unless you were incapable. But to me the sound of FLEX takes the idea of a web developer away from them in a drag and drop environment that handles middleware (coldfusion), MXML (whats the M for?!?!??! another non standard version of XML? pity), databases and front end client applications (flash). Take a read of this article it is truly informative beyond just FLEX knowhow.....
http://www.theopensourcery.com/osrevFlex.htm
http://www.theopensourcery.com/osrevFlex.htm