I am no expert, however I started with Derren Brown's book Tricks of the Mind. It provides a solid basis on how to actually hypnotise a person, and a lot of personal thoughts of his on various aspects of hypnosis, such as what it is, why certain things work, and specific techniques. This is all supported by a fair few anecdotes of his, some of which are very interesting to read and are chosen to make fascinating points about hypnosis itself.
The next book I've read is Reality Is Plastic by Anthony Jacquin, which is a much more structured step by step approach, its more of a tutorial so its pretty dry to read, but very informative. It follows steps and techniques in a chronological order for someone to learn hypnosis. I say its a book, but its actually a spiral bound notebook printed on cheap paper that is actually very thin. Sure there is more than enough information in there but its very dense and streamlined, considering the price and physical properties its a bit meh. Anthony is very commercial with his hypnosis so sometimes his videos are a bit hard to get through.
I consider hypnosis a fairly strong personal journey, so I feel a bit like once you've sorted out your ethics and covered some basic principals on how to make it work its mostly personal development from there, these books are good for reference however I wouldn't follow them very literally. Definitely watch some videos of the author performing (If you aren't familiar with these people) before you buy their books and decide from there, also look at other hypnotists too.
As far as DVDs go I'm not really sure. The only one I'm aware of is The Manchurian Approach, also by Anthony Jacquin, and I'm pretty sure its more or less a video form of his book. I think it follows the progress of an absolute beginner as he teaches them the content of the book. If you want to learn from someone, and you have some experience, you can more or less watch them perform and do it as there shouldn't really be anything secret or behind the scenes going on.
There are also seminars available but that depends on where you are and they tend to be pretty expensive in comparison to a book or DVD, but its said that that is the easiest way to learn.