Looks like adobe decided to open source flex. What does this mean? well, it looks like they are open sourcing the sdk. This is the part of flex that is already given away for free. The part that hasn't been given away - opened up is the code for the components. Previously you had to purchase flex builder to get the code for the components.
Here's a couple of interesting links. video interview with members of the adobe flex team on open sourcing flex
overall, i think this is a really good move for Adobe. This gives them a way to compete with microsoft and puts them more in a psycological instep footing with the java community. It seems like Adobe has very much gone after the java community when trying to market flex. I think this just gives them "street cred" with the java and other open source development communities.