A simple newsletter is a very effective way to keep in contact with your email list.
You can design one yourself with a word processor or better yet, use Microsoft Publisher which has many templates for newsletters built in.
You can also use an automated email company to send out your emails also. I recommend constantcontact.com and icontact.com, there is a fee to use this service but the newsletters look great.
Add links to website
Add audio files
Make your newsletter simple and easy to read. Make it one short page with no more than three paragraphs of information.
With a newsletter you can add pictures and audio files (as an attachment) so it is an effective way to market yourself.
Remember most people do not spend a lot of time reading long emails because we all receive so many emails every day, so make it simple and to the point.