UPDATE 1: Flash Builder 4, BlazeDS 4, and Spring 1.0.3 have all been release so you no longer have to use beta or nightly builds of these products. Use the production versions! UPDATE 2: I've done a second part to this screencast that combines Flex 4, Flash Builder 4, Spring 3, BlazeDS 4, and Hibernate 3. UPDATE 3: A Refcard on Integrating Spring 3 and Flex 4, which I co-authored, is now available! It provides a step-by-step tutorial for setting up everything I show in the video below. Connecting a Flex 4 application to a Java / Spring back-end couldn't be easier in Flash Builder 4's new Data Wizards. I've recorded a screencast that shows how to set up the web application project, configure Spring & BlazeDS, and then build a Flex 4 application that connects to the Java / Spring back-end. Check it out and let me know what you think.