Hi there. This plugin actually works pretty well for me in IE 8.0 and in Firefox 8.0.1 but it doesn't work in Firefox 8.0. (I have 2 computers with different versions of Firefox on each.)
Issue 1: In Firefox 8.0 it does not resize the body text, just the A's that you click on.
Issue 2: In all of my browser versions, the A's resize. On other websites / blogs that I have seen that have this done with CSS, the A's don't change sizes.
Issue 3: A small link underneath the A's that says "Reset Font" would be immensely helpful! It would take the user back to the original size.
Also, on a minor note:
Admin menu --> Settings --> font-resizer needs to be in capitals to match other admin plugin titles.
Thank you so much for writing this. It is very much a needed plugin!!!