Tell your users to use Firefox. I've found that it's text size changing feature always work, and IE's hardly ever works.

You can assign a font-size: xx%; to the 'body' tag in your css file, and then change all your 'px' font sizes to 'em'... This is the more "web accessible" method since most, if not all, browsers will be able to change font size, either through their menu or keyboard shortcuts...

[edit: the reason IE's font size changing doesn't work is not the fault of IE. If a page has fonts set in px then IE won't change the font size. If a page's fonts are all set in ems, then IE will change the font size no problem].

jj.