For some reason you want to grab those cool video files from Youtube and turn them into SWF (flash file). This is the most easiest technique.

1. Go to Youtube and search for your video.

youtube

2. Get the video url

e.g. http://www.youtube.com/watch?v=dLCskUI6cS0

3. Go to Keepvid.com

keepvid

4. Paste the video url from Youtube then select Youtube as your video source from the drop down list of video sources. Click the download button to download an FLV copy of your video file.

5. Now you have an FLV file of your video. You should then convert this into a SWF file by going to Media-Convert.com

media-convert.com

6. Browse your input file and select the correct format
7. Choose an output format (SWF)
8. Accept the terms
9. Click the convert button.
10. Wait for your download to finish