There's a really impressive collection of free ebooks on the eLearning Guild website.
The latest one is Tips for Producing and Managing Flash-based e-Learning Content. In all there are eight ebooks there dating back to 2005 and they are all free to download.
Each book is a collection of tips and they cover topics from choosing the best LMS (learning management system) to tips on beingg an online trainer.
These all look well worth a read.