The HCI SmorgasbordThere are so many interesting UI links, resources, articles, and papers out there. I'll have to create another low sidebar for easy reference to them.
HCI Publications (from HCI Bibliography - comprehensive, informative, up-to-date)
HFI's UI Design Update (I like to also browse the entire site)
The Usability Methods Toolbox
Shneiderman's "Eight Golden Rules of Interface Design"
Heuristics for User Interface Design - Nielsen
Paperprototyping.com and the author's most recent article Six Signs That You Should Use Paper Prototyping
comp.human-factors (Google groups)
Human-Computer Interaction (HCI) (Yahoo! directory)
Web Usability (DMOZ directory)
[Paper] Why GOMS?
[Paper] Providing design knowledge to system developers by domain-specific style guides
Good ol' Ask Tog. :)