From the Business of Software social network:
"Usability testing is important, but you've got other things to do. In this video, Steve Krug [author of Don't Make Me Think] ... talks about informal usability testing and how the minimum of work can give you extraordinary results."
Update: Ignore the Code has several good articles, like Usability Testing: It's not a Myth, Flatland, and Designing with Data. This was in one post:
The Science of Aesthetics by Keith Lang from Keith Lang on Vimeo.