PDFmyURL is a great little website. As the name suggests it turns any website into a PDF. Simply browse to the site enter the address of the page you would like to turn into a PDF and press the orange P shaped button. The site will work its magic and in a couple seconds your web browser will ask you if you want to save a file. In the example below it would ask to save ‘www.uua.org.pdf’
Edit: We also have a post explaining how to turn a document like a PDF into a website.