I bought this book on the recommendation of several people, and basically this is by far the most well known, modern book on the topic. It covers the history, business, laboratory setup and design, media selection, sterile technique and even a short section on Genetic Engineering with Gene Gun and/or Agrobacteria.
Frankly, all of the above information can be had rather easily online and it isn’t in depth enough to be helpful if you are really looking to pursue this as a business, but the real value of the book comes in its kind of encyclopedic listing of media choices for plant species, this is very helpful and can be a guide to the budding Tissue Culture-ist as they venture out. I recommend this book for people, like me, who are starting out in Tissue Culture and who need a guide or Bible to help them illuminate some of the uncertainty as they get started. Well worth it.
Josh Melnick's Biology Blog 