This is only supposed to happen when you're not using a Web-safe font. It's set up this way to prevent Web newbies from using WhateverFont and it looking fine on their computer, but not realizing it's getting randomly substituted on everyone else's computer, because they don't have WhateverFont installed.
Stick with standards like Arial, Verdana, Times New Roman, etc., and you should be fine.
Can you post a link, and maybe a screenshot of the page in iWeb with the font selector visible?
Sorry, but it turns out I can't tell from a screen cap. I thought I might be able to. I'm wondering if it used to be a non-standard font, and you changed it back? Just a guess.
Either way, that site is a mess. Everything opened up in new windows, and it looks like you're trying to get into the Guinness Book of World Records for using the most font sizes, styles and colors. Sorry. I had to say it. 🙂
Post your question in the Web design section, along with the links you posted here. There are some iWeb smart people there. I'm sure someone can help.
No, it's always been Arial.
And, re. sizes and colours, they're all in keeping with my brand, not just random, the colours (white/red/blue), and the sizes (and indeed colours) are just to differentiate the different sections and attempt to draw attention to certain parts. I know where you're coming from, but slight exaggeration perhaps 🙂