Anything by Seth Godin is good for what you are looking for. I also really like collaborative books from a variety of successful entrepreneurs, as online marketing is as creative as the person behind it. Some that I have read and liked include Conversations with Millionaires (Mike Litman) and Success Alert (John Evans) and The Myth of Passive Income (Joe Vitale).
Seth Godin you can find at the library or on Amazon - or of course any of his sites. I have some information on the other two on the main site:
http://www.selfstartersweeklytips.com/r ... -alert.htm
http://www.selfstartersweeklytips.com/p ... income.htm
I look forward to hearing other recommendations!