Right, what we're going to do here is create a form that will (if you're browser supports frames) go on the left hand side of our frames page. If your browser doesn't support frames, then just ignore all references that I make to them, and just build the forms page.
First of all, create another new HTML file. Give it a header and define a background colour, and text etc... however you want them. I encourage the use of lighter colours for backgrounds, because generally they're less hard on the eyes to look at.
Give the page a heading, saying something like "My Guestbook". Now define a form, and have some text inputs for the visitors name and email address and homepage address. Then have a menu that allows the visitor to select how he came to be at your page. Then maybe a textarea of moderate size in which they can put their comments. Finally, have two buttons, one to Submit the form, and the other to Reset it. Format the layout of the page as you see fit.
Once this is done, add a link to it from your main page, saying something like "Sign My Guestbook", and have that link targetted into the left hand frame on your frames page. To make this work, unfortunately, you'll also have to create a totally empty HTML document (apart from an <html> and a </html> tag pair), and define it as the intial source of the "left" side of the frames page. Then all you have to do is click "Sign My Guestbook", and hey presto ...