Now that the NDA has been dropped for the beta, are we allowed to put ads on our YouTube videos of game play?

It's best to contact an Administrator about questions like this, or contact Bethesda/Zenimax directly.
Info from anyone else may not be completely accurate.

I will link you to this post from December regarding a similar question, from an Admin Gstaff: http://www.gamesas.com/topic/1481537-fallout-nv-youtube-copyright-permission/?p=23209030