Here's an easy tutorial on how to grab a video off of Facebook and place it on Youtube.
To do this you'll be needing:
Once you've installed the Firefox extension, and restarted your browser, go to the video on Facebook that you want. You'll see these new links added by the extension:
Save the video to your computer; right-click on "Download Video" and click "Save Link As ..." from your menu:
Once the video has finished downloading, login to your YouTube account and click the "Upload" link:
On the next screen, click the yellow "Upload Video" button.
After clicking the button you'll get a dialog box asking to select the video you want to upload. Select it and click the OK button. It'll start uploading the video. After that just set any titles, tags, etc., that you want and you're all set!