Screen capturing web pages has always been really difficult. If you use Google Chrome web browser, there is a great little extension called Screen Capture (by Google) that enables you to capture the entire page.
Chrome has been my workhorse web browser. The simplicity and performance of the browser has been a big hit on me. Now with this tool, it is great to capture an entire web page (beyond what you see on your monitor) and generate either a JPEG or PNG file.
Great for capturing web site pages for presentations or reviewing designs. As shown in the options window, the ability to also capture a page region, only the visible content, or what I like is to capture the entire page. Another feature is the ability to setup hotkeys to assist when I need to kickoff the tool with quick keyboard strokes.