Have you heard of schema.org? They are working on terms for describing  
resources that will be useful to search engines - so everyone who  
wants to be noticed is working with them!

The AccessForAll accessibility work that has been discussed here  
several times is included. The 'Benetech' project will bring several  
hundred thousand resources online with accessibility descriptions. If  
you are interested in this project, go to https://wiki.benetech.org/display/a11ymetadata/Project+Overview 
  and check it out.

As co-editor of the ISO/IEC JTC1 standard for accessibility, I am  
participating in this work, and proposing to duplicate it in our  
proposed application profile for accessibility of learning resources  
for which I am the lead editor. This is likely then to become European  
standard and to be adopted in many countries that participate in ISO  
work. So this is important work :-)

Please send any comments you have either to the list, to the project  
or to me and I will raise them in our working sessions...

Liddy