Beyond Bullet Points by Cliff Atkinson. It's a Microsoft sponsored book about how to use PowerPoint and it looks specifically at how to avoid the evil, coma-inducing bullet points.
He has a great thesis that will make every presentation better. Basically, you are dealing with an information bottleneck when you are presenting. You, as the presenter (preacher) have a lot more information to impart than the listener can possibly get at one time. It is just as bad to overload them with information as it is to underload them. Too much and they shut down and don't get what you're saying. Too little and they drift off for lack of engaging structures to help them assimilate the information.
This makes your goal giving just the highlights of your information using a structure that is familiar to your listeners so they have a way to organize what you're telling them. One example that comes up in the book frequently is that of the checklist - a checklist is something that everyone knows about, so you can use it as a template to organize your information so that people can easily grasp it.
Another great take-away from Beyond Bullet Points is the idea of using a story board for your presentation. Before you start building your slides you plot your story arc - you find your characters, conflict, and setting and sketch out where they are and where they are going. If you are familiar with the Lowery Loop, this will be a similar process, but with the visual element added.
Overall, I would recommend what this book has to say. There are a lot of great concepts in here that will be helpful for presenters of any type. However, for preachers, there is a lot to wade through to get to the good stuff. Mostly what will help you is in the first few chapters - after that it gets pretty tedious. This would be a good book to borrow from the library or a friend.