why not use seperate pages, why keep it on one page?
This is quite a big thing that many new webmasters do not know/care about, but it is important as you learn, since later on it will be whether you are hired or not.
It is called
SEO, or Search Engine Optimization, and it is a science of it's own. It is always better to have seperate pages, Iframes break a lot of search engines.. I would not worry about having iframes at all, just reuse the design on each page.