You could use any word processor to write your newsletter. I think it would be very important to create a template, so that you don't have to recreate it every time.
If you're not familiar with templates, open MS Word and click on "File" / "New". You will see some templates you can use, and a link to the Internet where you can download others. I would assume Corel's Word Perfect would have a similar setup.
You could also look for "3rd party" software written for this purpose, like this one:
MS Newsletter Template(Please note, I'm not familiar with the product linked above and am not recommending it, just pointing it out. The page does have some "pop-ups").
This page discusses writing a newsletter using Word 97:
Newsletter in Word 97Note: the link above is to a "cached" page. As I write this, the actual page is not available. When you open the link, there is a link to the actual page and you can try that, though you could also just read the material from this cached page, too. I don't know how long Google will keep the cached page available.
If you're going to be doing this for a while, I would think the Publisher program would be worth the money if only for the templates.
I hope something here helps!
Dwight