Reverse Email Lookup the Free way
http://www.reverselookupguru.com/reve...
This video will show you some free ways to do a reverse lookup on an email address, or to use a name and find the corresponding email that way.
Its important to note that these methods might only work half of the time. I'll say this, its much easier to find a publicly listed email address, such as a business or organization on the net the free way than it is a personal address.
You can use the methods that are used in the video, and you may have success, but if you don't find what you are looking for - please don't shoot the messenger ;)
Your best best would be to use a professional reverse email lookup like the one mentioned above ^