ImageReady CS2 can also save animations as Flash files as well as the usual GIF format. It's easier to use ImageReady for this since its Animation palette lets you set the duration of individual frames, and it offers tweening (automatic creation of "onion skin"-type intermediate frames between key frames) to create smooth animations.

Photoshop CS2 also sports an Animation palette with the same features, but it can't save or export the animation as a Flash file. ImageReady can export it to SWF but doesn't have all the vector tools that Photoshop has — not even a Pen tool.

Solution: Create the vector animation in Photoshop using its vector tools, layers, effects and Animation palette features including tweening and timing options.

Then, click the "Open in ImageReady" button at the bottom of the Tools palette. The same artwork opens in ImageReady, vector shape layers intact. Choose File > Export > Macromedia Flash SWF, and there ya go. Best of three worlds.