Top new features of Adobe flash CS3
(Taken from Adobe.com)

Improvements made to:

• file import, such as support for PSD and AI files. You also learn about new ways to integrate products, such as the enhanced workflow between Flash and Adobe® Device Central CS3.
• drawing tools in Flash, such as enhancements to the Pen tool, and the brand new primitive drawing tools that let you create shapes easier.
• video components and cue points in Flash and Flash Video Encoder.
• debugger and coding tools in Flash, and changes to ActionScript. You will find a side-by-side comparison of ActionScript 2.0 code and ActionScript 3.0 code. You'll also learn about, and how to use, a document class in an ActionScript 3.0 application.

Changes made to the Flash workspace - Visually modify components' look and feel with the drawing tools — no coding required.

New features in the Flash authoring tool, such as control over the color of your bounding boxes, new copy-and-paste functionality

Convert animation to ActionScript - Instantly convert timeline animations into ActionScript™ 3.0 code that can be easily edited, reused, and leveraged by developers. Copy animations from one object to another.

Enjoy a new, streamlined interface that emphasizes consistency with other Adobe Creative Suite 3 applications and can be customized to improve workflow and maximize stage space.
ActionScript 3.0 development

Adobe Device Central - Design, preview, and test mobile device content using Adobe Device Central CS3, now integrated throughout Adobe Creative Suite 3. Create and test interactive applications and interfaces viewable with Flash Lite™ software.
Rich drawing capabilities - Visually adjust shape properties on the stage with smart shape drawing tools, create precise vector illustrations with the new Pen tool inspired by Adobe Illustrator, paste illustrations from Illustrator CS3 into Flash CS3 Professional, and more.

Advanced QuickTime export - Render content published in a SWF file as a QuickTime video using the advanced QuickTime exporter. Export content that includes nested MovieClips, content generated with ActionScript language, and runtime effects such as drop shadow and blur.

Sophisticated video tools - Create, edit, and deploy streaming and progressive-download FLV content with comprehensive video support. Ensure the best video experience with a standalone video encoder, alpha channel support, a high-quality video codec, embedded cue points, video import support, QuickTime import, closed captioning, and much more.
Timesaving coding tools

Save coding time with new code editor enhancements. Focus on relevant code with code collapse and commenting, and jump to code errors with the error navigation feature.

Click Here for the Top New Features in other Adobe CS3 Programs