Here is a list of books recommended by Tom Kuhlmann (Author of The Rapid eLearning Blog) to help with developing effective eLearning. The links should take you to their listings on Amazon.com:
Slideology: lots of good examples and overview of presentation design concepts
Beyond Bullet Points: learn to structure content that is very relevant to instructional design; plus it includes the essentials regarding cognitive load
Don’t Make Me Think: web usability and navigation; good examples and relevant to moving the learner through a screen