Social design, in my opinion, is a design with the objective to raise awareness and potentially make a difference in certain issues in a creative and appealing way. It could be a highly publicized form of design that many people get to experience. Social designers can come from anywhere. An activist with a creative approach to getting their information out to people could easily be considered a social designer.
Available resources for social design could be any type of social media or news. These things could help fuel inspiration and motivation to stress social problems in creative ways. The best and most interesting part about social design is that as long as there are social problems then there will be a need for social designers to produce their work and broadcast their opinions and stands.
Erin Lucas Design for "Save the Music"
http://socialdesigner.com/products/erin-lucas-tee-for-save-the-music
Cameron Tonkinwise Amplify Creative Communities
http://www.core77.com/blog/featured_items/politics_please_were_social_designers_by_cameron_tonkinwise__17284.asp
http://gliving.com/lightweight-emergency-shelter-no-dreaded-ikea-moments/
http://blogs.nd.edu/social-design/industrial-design-projects/revolution-wheelchair/
http://inhabitat.com/jointhepipe-brilliant-water-bottle-wins-2010-dutch-design-award/
http://inhabitat.com/artist-jan-vormann-uses-legos-to-repair-war-damaged-buildings/