[Scottae]

I wanted to check out FlashDevelop since it seems some of the guys where I work use this to do their AS 2.0 class editing. The thing that intrigued me is that their latest beta version can edit AS 3.0 classes as well as AS 2.0. It will also edit MXML, XML, PHP, CSS, HTML, etc. It's free and it's a light download (about 3MB) and a quick install. So until FDT 3.0 comes out, I think I will be using this to do all my AS 3.0 class development. Check out this page to see a list of features and links to resources. Here is their official page on the OSFlash site.