Here are several interesting links to sites and papers that you may find interesting or useful.
Let me know if you find any other great resources.
A web site that comments on current design topics with several articles about sketching books
Sustainable design Education
http://edutoolkit.designersaccord.org/how-can-we-communicate-best/
Design & technology teaching resource
http://www.ngfl-cymru.org.uk/vtc-home/vtc-ks4-home/vtc-ks4-dandt(2)
Design Feast
http://www.designfeast.com/
Design search engine
http://www.infomat.com/
Free images and search engines
http://elmo.academyart.edu/find-resources/digital_images.html
Google patents: if you think your design is new do a search for it!
https://www.google.com/?tbm=pts
Design Knowledge repository
http://www.designophy.com/
Internet Public library
http://www.ipl.org/div/about/