Is watching free movies online legal and ethical or is it a form of stealing with copyright laws being broken?

Depends on the movie and source.

Comcast has loads of free movies, not illegal to watch any.

Like CUrlyben states... it depends on where you are watching them. THere are Illegal sites, and there are legal ones... it all depends on if they are paying the required royalites or not. Assuming the material isn't considered public domain due to age.