I've been wrestling with the same problem. I'd like to have an "updated on..." and "Copyright" etc footer on my main web page .... but can't figure out how to do it!
If you make a text box and try to drag it into the footer, the page just extends to prevent you from going there. If you click on the footer it's framed, but then if you click on Text, a blank text box just appears in the middle of the page.
My patchwork solution was to switch to Appleworks, make a text box, type in the text I wanted, then cut and paste into my footer. (iWeb apparently thinks it's a graphic, then.) Seems a bit lame, though. Any other ideas out there?