HP's Stan Garfield published a useful set of KM Resources in a Line56.com article back in February, Setting up a KM Program. He lists Books, Periodicals, Blogs and other Web Sites. It's nearly impossible to list everything in any one of these categories. I've provided my own list of KM blogs in the past.
UPDATE: Stan has moved these resources to his GooglePages: http://stangarfield.googlepages.com/kmresources.