Truthfully, when I sat down in the theater to see How To Train Your Dragon I was really going for the kids and was expecting a nice little kid movie. I was wrong, so wrong, and I found myself laughing, crying, and truly loving it. I even sent my husband back to see it the next day. There are so many moral themes explored and one that I appreciated was how it speaks to the labels we give people and how often we think we have all the facts and make many assumptions about people's (or dragon's) motives and are so wrong. But as much as i enjoyed it, I am glad I left my youngest child at home. I think this movie could be visually scary to little kids and I would advise reading the detailed reviews from plugged in and movieguide to decide if it will be a good fit for your family and at what age a child is ready. It is targeted at 8 and above.
For homeschool, this movie would be a such a fabulous way to kick off a 'viking' unit! If you don't have time to do a long unit you could do 'viking week' and do a lot of these fun projects or even just have one fun "family night" and pick one thing to do together and watch the movie with a big viking feast:
Set in the mythical world of burly Vikings and wild dragons, and based on the book by Cressida Cowell, this action comedy tells the story of Hiccup, a Viking teenager who doesn't exactly fit in with his tribe's longstanding tradition of heroic dragon slayers. Hiccup's world is turned upside down when he encounters a dragon that challenges him and his fellow Vikings to see the world from an entirely different point of view.