Hello,
You can smooth it out using Flash CS3 by doing one of the following:
1. Increace the Frames Per second of the Flash ( try 24 FPS )
2. Slow down the scroll speed when creating Flash content ( Timeline FPS in Flash CS3 )
3. Increase your CPU by getting a faster PC
In Flash 10 Adobe has now included Hardware acceleraion which should make Flash content run MUCH smoother but we have not yet to try it.
Hope this helps,
Sean.