Elearning - accessibility and usability

designing online courses

The accessibility standards for elearning are exactly the same as web design. You need to follow the W3C WAI guidelines and criteria.
Some useful links: : The source of web accessibility standards. Start with:
These days, you should focus on the Web Content Accessibility Guidelines version 2. See: : Checks individual URLs or files
Another web-based tool : - There is a paid-for desktop version, which allows checking of whole elearning packages offline:
Also, look at the RNIB pages on accessibility, and the Shaw Trust. Both of these provide services that will help you assess your content for accessibility - although the Shaw Trust is more general, as it includes testing with people who don't use a mouse/trackball.
With usability, there are no hard and fast standards, but, again you should follow general web conventions (which I'm afraid most elearning materials fail spectacularly to do). Jakob Nielsen's site is a good place to start - although follow what he says, not what he does.
At this point, I'm going to quote from Stephen Downes superb essay on Principles of Effective Elearning. It's five years old, but still entirely valid:

Between [Yahoo and Google], designers have hit on what are probably the two essential elements of usability: consistency and simplicity

Universal design

page of links on universal design principles