Arial is one of the web safe fonts and should view the same in FF or IE. If
possible please post a link to your website so we can see an example of what
you are talking about. In the meantime...
I would check first to see if your text has been converted to an image. In
the previewed page in FF, try to select some of the text by left clicking
and dragging across the text. If you can't select the text that means it has
been converted to an image which will change the appearance. And if it has
been changed to an image, that is because of something you are doing in your
design. With older versions it was overlapping design elements, but without
seeing your page it is hard to suggest what might be causing it.
The second thing I would check is the paragraph or text style. When you
select the text in the Pub doc look on the formatting toolbar, to the left
of the font type to see the text style. If it says something like Body Text
3, then click the downward pointing chevron and choose "clear formatting",
which will result in "normal". Now see if your output looks the same in FF
and IE. It may be that Publisher cannot convert the text style you have been
using such that it appears the same in FF and IE.
And finally, I would consider looking at Tools > Options > Web tab and
perhaps changing the Encoding. If you are using UTF-8 then try Western
European...or the other way around.
DavidF