References

Yale C/AIM Web Style Guide
A compendium of good advice, and, other than their error in using the FONT tag, a good example of a navigable document.
Usable Web: Guide to Web usability resources
Good collection of links to resources and articles on usability.
The Alertbox: Current Issues in Web Usability
Jakob Neilson's column about Web usability issues. Much interesting material here. Of particular interest are Changes in Web Usability Since 1994. Another paper by Neilson is Sun's New Web Design.
Metaphors and the Net
An exploration of seven different metaphors for the Web, only one of which (conceptual space) is in common use.
Web Site Usability: A Designer's Guide
The page about a book written about research done by User Interface Engineering. The excerpt here is an eye-opening summary of why links do and don't work. Other material on the site is useful too. The book is probably worth buying ($40).
Designing Large-Scale Web Sites : A Visual Design Methodology
Darrell Sano's book on Web-site design. The only chapter that lives up to the book's title is chapter 3, but that chapter has excellent material in it. Full review.
Multimedia and Hypertext: The Internet and Beyond
The "Internet" part of this book is an afterthought, as the book focuses on hypertext research up until the early 90's. Still, useful and informative background material. See Features Missing in Current Web Browsers for Neilson's perspective on what Web browsers should do.
Web Review
A site full of excellent columns and solid technical advice. Finding what you are after from the front page can be difficult, though, so even these guys need to looks at their navigation more...
Web References
Another site full of excellent columns and solid technical advice.
World Wide Web Usability
A special issue of the International Journal of Human-Computer Studies, on Web Usability. Contains a collection of papers, academic in outlook.
State of the Art Review on Hypermedia Issues And Applications
A literature review of hypertext issues. Theoretical orientation.