Nick Usborne writes "Four Ways Good Newsletters Are Like Blogs."
I personally think a blog is a good companion to a newsletter. Mainly because with a blog, you can post your thoughts, links to other sites, etc. on a daily/weekly basis. Then at the end of the month (or quarter), write your newsletter and point to the blog for "the full story." It makes it a lot easier to put together your email newsletters.
If you haven’t started a blog yet for your company, you should give it a try with Blogger.