Yes there is. When you create a post, there is a box you can check/uncheck next to the "post" button that says 'email me replies to this post'. If you missed it when you first created the post, you can click the "edit" button in the top right corner of the post and it will pop up again so you can make sure the box is checked.
Having said that, I just posted this and noticed at the top of the post, it says "previous", "next", and "email me replies to this post". I guess that's easier!