Excellent work here from the BBC with the launch of its learning design toolkit. If you design or deliver online learning then this is well worth a look. What is particularly pleasing to see is that the emphasis is on the learner and how they like and want to learn rather than thinking first about content and delivery.
Usability is key to the experience, but do those designing elearning put usability high up the priority list?
take a look at theses resources - they will help you in designing you next elearning offering.