Egrabber Email ID Extractor is a useful tool that does exactly what it says, extracts emails from websites. It is a desktop tool that must be loaded on your desktop. It works very well and is extremely quick. The plug-in installs in your browser toolbar. Upon clicking on it, it will extract email IDs from a web page, de-dupes (or eliminates duplicate copies of data), sorts and displays them for you in an Excel and Outlook friendly format.
There are a lot of these tools out there and you need to see which one works best for you. That said I believe in having more than one of any tool as you never know when they will go away or change. Take a look on how to use it.