create a second html page and keep it as basic as possible, very few images, nice size text and experiment with table widths so that it prints onto an A4 page ok.
have a link on your original page labelled "printer friendly" or soming similar which redirects them to the page that you have just created. That way they can print out the results in a format that is easy to read and fits on the paper.
in fact, refer to phpbuilder.com's way of offering a printable page by looking at the articles. scroll to the bottom of a page and you will see the link to which i am referring.