Reverse Email Lookup
As you probably know, claiming an email address is as easy as 1-2-3. And more importantly, you don't even have to input your real information to get one. This means that finding someone's email address just by their name can be extremely difficult to say the least.
The best way to do it is to use the likes of Google, Yahoo or Live to search for their name in quotation marks so that all the results that come back are matched exactly to the query you sent. If you do this and then scan the first couple of pages of results for anything that might lead you to to what you want, then you should find at least something.
Failing that, you've then got the likes of MySpace, Facebook and Bebo. These allow you to see people's personal profiles AND almost all of them have email addresses listed on the page. If you search the sites with their own search facilities for the person's name you're looking for, then you should pick up any results if they have any.
Alternatively, you could use a service such as Gov-Records.com to give you access to their database of millions of people (and their email addresses).