If you are comfortable with Word (and you don't want to spend a lot of $$$ for software), try Microsoft Publisher. It's very easy to use and it is compatible with Word. It's not too expensive and it can be used for a variety of things, including newsletters.
One thing: I take it that you are printing these yourself and not having them professionally printed, right? If you are working on a small scale, Publisher works well. If you are printing hundreds of newsletters and having them professionally printed, Publisher is not your best option.
Hope this helps! I work in graphic design and layout.
