The Flash Blog reports that Adobe will start calling all upcoming versions of the Flex Builder as Flash Builder. Flex Builder is an Eclipse based IDE for creating Flash web applications and Adobe Air applications using a the Flex framework.
The Flash Builder will still use the open source Flex framework for developing rich internet applications, the new name is simply used to clear any confusion as to the product created using this tool – it creates Flash movies in SWF format that do not require anything other than the Flash Player to run.
While this might help clarify that Flex Builder is essentially a product to make Flash content, this might create confusion between Flash Professional and Flash Builder as people might wonder what the purpose of Flash Professional is if Flash could be built using Flash Builder.
The beta release of the new version of the Flash Builder is expected to come out this summer. You can learn more about this from here.