Matthew Reidsma of Grand Valley State University gave a talk at ALA Annual 2012 on Responsive Web Design for libraries. He led off with a discussion of the basics of Responsive Design and how it can benefit your library, and then spent the next hour walking through how to build a responsive site by tackling the elegant http://lollibrary.org website.
Other formats, including video with slides, are available at http://matthewreidsma.com/articles/23.
