My oldest son is nine. I have not allowed him to have his own email yet. I have seen so many news articles about the kinds of predators out there on the web. But, I like the idea of him being able to have correspondence with his grandparents.
I have come across this email program that looks interesting. It has many interesting features. It Allow your child to only receive and send emails from people in their contact list and a copy of incoming and outgoing messages are sent to the parent. You can remove images and links within emails. You can choose to only allow specific attachment types such as: images, pictures, video, mp3s, zip, pdf, Word, Excel, Power Point, etc. Parents can chose to approve or deny any email sent to your children via the mail queue. Filters include offensive words and spam. Kids can adjust the look of their account by choosing from several fun templates.
My favorite part though is the time restrictions. Parents can choose to restrict times of the day and days of the week that their child can sign on. Parents can even restrict their child for a certain period of time and show a custom message if they attempt to log in!