Flex SDK 3.1 and Flex Builder 3.0.1 Released
Matt Chotin has posted an article about the release of the latest version of the Flex Builder version 3.0.1. This Flex Builder update includes the Flex 3.1 SDK along with a number of bug fixes and certified versions of the professional data visualization and testing components.
To manually initiate an update to Flex Builder using the Adobe Updater, open Flex Builder and go to Help > Search for Flex Builder Updates...

But frankly speaking, i don't quite agree with some points Matt Chotin emphasized in his article about the Flex Builder