Tim O'Reilly has a blog post on Zorn - Macromedia's Flash tool that will run on Eclipse. Tim is on the Board of Directors for Macromedia...

Macromedia's announcement that their next generation enterprise Flash development tool, code-named Zorn, will be built on top of Eclipse, is a watershed moment both for Macromedia and for the open source movement. Macromedia's choice of Eclipse speaks volumes about the impact of open source on commercial software development -- and about Macromedia's commitment to making Flash into an essential platform for next-generation internet applications.

Tim also mention's that the lead developer of Zorn is Mark Anders, was one of the original developers, and project managers of ASP.NET at Microsoft.

Mark told me that he joined Macromedia because he felt there was a need for a real enterprise level development tool for Flash.