How did you try to email the video?
What I found is that the following procedure will convert the movie to fit an email:
-in iMovie export to CameraRoll
-open your movie
-hit the arrow button and export to email
In my sample movie, the size went from originally 150MB to 3.5MB and could thus be send via email. Needless to say that the quality was very low. But the problem persists that if the movie is longer than 1minute, it cannot be send via email.
Your YouTube option is the best way to go. If you wanted to share the movie with friends, upload the movie as unlisted and just send everyone, you would like to see the movie a link.