It sounds as though you want something not poker related, and even if you did want something poker related, I doubt you'd be able to find many legitimately useful books that somehow blended poker and things like internet marketing.
Even if you were hoping that your other business ventures were somehow related to poker, like if you got a job doing internet marketing for one of the poker sites, I think you'd still be better off just reading normal books on marketing and then blending those concepts with your knowledge of poker.
I assume you also aren't looking to shell out the $150-$200 that most university business textbooks cost. Take a look at this list maybe:
http://www.amazon.com/Best-Business-.../RN7CO82QAZ47Z
The main problem you're going to have is that most business books that are not textbooks and priced like normal books aren't designed to teach you the technical aspects of how to perform in that field, which is what you need. I almost feel like you might be better off just picking up some used textbooks which would probably only run around $50. If you really can't stand the blandness of a textbook, the first two hits for "internet marketing" on Amazon sound kind of interesting actually...
http://www.amazon.com/s/ref=nb_sb_no...keting&x=0&y=0