I've owned Macs for as long as they've been around. Normally if you are having issues with font size in printing, check the page setup like Karen said. It may be set up to print many times larger. I don't use outlook express or internet explorer on my mac either, but if your mom is using OS9, she might not have too much of a choice. Personally I use Firefox for my internet browser and I use the Mail application (just called Mail) on my laptop. Thunderbird is good for email as well, and it might be an option for OS9. Safari is another decent browser as well, and was made by Apple as the default browser.

One of the teachers at school has a problem with her email every now and then where it prints all the letters of the email backwards!! It will still be all set up correctly on the page (left justified), but the letters are all backwards! It's bizarre! She still hasn't figured that one out!