Kate-I think to save the video you should try this:

1. Go to the video in facebook and right click it to get to the save option
2. Save it as a .wmv or quicktime movie, whichever is available
3. In the post window on the blog, click the "filmstrip" icon (to the right of the picture icon)
4. Browse to the video file you have saved
5. and voila! (I hope)

Can you tell I started out my career as a technical writer or what?!!? Granted, this is not written in proper tech-speak, but I can't seem to get away from numbered lists now when I'm giving computer directions!