I do the image creation in PhotoShop, and then layout moments in time of animations and interfaces in Freehand. Experimenting with the concept in flash is very time consuming and expensive. This method allows me to study the design and visualize tactics that I can use to animate and move through the piece. Then when I'm done visualizing I collect some of the sketches and make a presentation board to present to the client. Many web developers discount the power of print as a presentation tool they are infatuated with the screen, but to me you use the right tool for the job and when it comes to selling a design It is print.
Print is stable predictable and most of all tangible.
I Swf export major moments in time from freehand to flash and then organize and start animating. I work back and forth with freehand and Flash to carry out the piece. Finally I create the sound loops and effects and then bring them into Flash. I use a few tools Rebirth, Groovemaker and Mixman. Sound is the thread that sews it all together it makes the experience real.