Here you can find some useful flex libraries,sample codes.This post will help you implement better flex applications. I used these frameworks in my projects.
Using following libraries you can achieve some functionalities like generate pdf,components moving and resizing,diagramming,create pdf viewer.
Cairngorm Framework – You can build flex applications that apply a form of the Model-View-Controller (MVC) pattern.
Parsley Framework – Using this Framework you can implement following things in your flex application.Flexible IOC Container,Dependency Injection,Decoupled Bindings,Dynamic View Wiring,Managed Commands,Object Lifecycle.
Object Handles – With help of this library you can create resizable and movable components in your flex application.
SWFTools – This package contains some useful utilities.Using pdf2swf utility you can convert any pdf to SWF File then you can load that swf file in your application I mean you can create PDF Viewer kind of application.
Flexlib – This Flex Component library contains lot of useful open source user interface components for Adobe Flex 2, 3 and 4.
AlivePDF – Using this library you can generate PDF file from your flex application.
as3xls – With the help of this library you can read and write Excel files in Flex.
Flex Diagramer – This Flex library helps you to build your own diagrammers and easily extend nodes and links adding custom functionality.
FlexWires – Create Drag and Drop Wiring UI Components in Flex.
Tweener – Create tweenings and other transitions via ActionScript code for projects
I hope above flex libraries are really useful while developing a flex application.If you know some open source libraries share the same via your comments.