Watching TV shows in English (with English subtitles) is a great idea, but I'm not so sure about The Simpsons. I speak English fairly well and I still have some trouble understanding the Simpsons (Homer especially). There are other shows that are much easier to understand and better suited for beginners.
For example, I would consider Breaking Bad much more suitable for beginners in English (most characters speak very clear), but it might not be an appropriate show for kids.
