The first thing you have to know is that your AH films are not really films as such. They are just game data that the film viewer is using to recreate the action you have filmed.
May sound strange at first, but you actually have to film whats happening in your film viewer
This is called capturing, and you need a program for that. One example for such a program is FRAPS, which is available in a free version.
Once you have captured the film, you may chose to edit it with a video editing software like Windows Movie Maker (free), Sony Vegas or others. Then convert it in an appropriate file format for Youtube, and upload it there.
For details on "how to", please check the Film & Screenshots forum.
