I should have posted these a while ago...

Alan Blackwell works on the cognitive dimensions framework as part of his larger research program on the psychology of programming and has many useful links to papers etc on his page.

Thomas Green originally developed the framework and has been the inspiration for a lot of the recent work on the psychology of programming.

Lastly, I've already mentioned this in a previous posting, but the Psychology of Programming Interest Group meets once a year to present and discuss some of the latest research in this field.