This component works with Flex Builder 2.0.1 or Flex SDK 2.0.1 and the recently released Flash CS3. The final version will be in the next version of Flex, code-named "Moxie".
That's what they write about this on the Flex Team blog:
We are particularly pleased with this feature, as it demonstrates our commitment to improving work between designers and developers and integrating Adobe products. Flash content can now easily become a “first-class citizen” of a Flex application. Simply extend your Flash symbol with our new UIMovieClip class, and you are ready to go further.
Read fully here . ')
Installation instructions here .
UPD:
Found a detailed example of using this component in the Jesse Randall Warden blog.