If you’re in the business of building Rich Internet Applications using Flash or Flex technologies, today is your lucky day. You’ll want to run, not walk, straight over to Adobe Labs, where you will find beta releases of the upcoming (and newly renamed) Flash Builder 4, the Flex 4 SDK and the highly anticipated Flash Catalyst.

In addition to the downloads themselves, there are a number of resources to help you get started. Tim Buntel has a “What’s new” article and video tour of Flash Builder, along with Matt Chotin’s article about the new SDK.

And with the posting of Flash Catalyst, designers and developers alike will finally get to play with the tool that I’m sure is going to revolutionize the way that applications are built. I’ve already had the pleasure of working with Flash Catalyst for quite some time, and I’ve been really impressed – not only at the quality of these early builds of a brand new product, but also at the willingness of the Flash Catalyst team to listen to and act on suggestions, comments and criticism. Now, it’s your turn to help shape these products. So, quit reading this and get downloading!