Gonna assume CS4 is same as CS5...
Way I do it is:
- take screen shot of every frame in video (pause and print screen every second), then save them
- open PS and pile all the screens into one file (one layer for every screen)
- at the top, go to window -> animation
- when animation window opens at bottom of screen, make new layer (frame) for every layer you have already
- select first frame and hide all layers in the layer window except for the first one
- then select 2nd frame and hide all layers except for the 2nd one
- do that until you're done all layers
- choose how many seconds you want each frame to last (there's a number under each frame you can click on)
- when done, go to file -> save for web & devices
- here you can change the dimensions, the amount of colors, etc
- click save
Can make picture if something's not clear
Also I'm sure you can Google around for something, don't know if there's a better way of doing this