This is the most popular book:
I have that book and also went to the library and checked out the 3 or 4 books they had on grooming. I learned a little from each one. There are tons of videos on YouTube, and some on other sites like the grooming equipment makers.
I bought an entire grooming course on DVD from ebay dirt cheap. The video quality is pretty bad, but I got it cheap so it was worth it.
I also paid a very skilled groomer for a private lesson at my house. She used to own her own grooming shop but now just grooms part time for a big petstore chain so she was willing to give me a lesson for the price of one groom!
This forum has tons of great info, so put the search feature to good use and you'll learn so much.
I am so glad I went the route of grooming Panda myself. Its fun, and I can give him touch ups any time. I cant imagine having to go 4 to 6 weeks between grooms.