I'd look at A List Apart and Signals vs. Noise for good advice, but learning about design is about exposing yourself to a lot of good and bad design — look at really well designed websites (like those made by HappyCog, SimpleBits, or Airbag Industries). Look at all the people who work there, their blogs, their work, their books — be inspired but never copy.
I'd also be wary of sites dedicated exclusively to 'user experience' design or 'usability', many of the principles of design have nothing to do with user testing, studies or HCI, and focusing to much on those things can lead to development of methodologies rather than sense. I'd recommend taking a class in communication design and learning about type. Good design starts with type and hierarchy — Thinking With Type is a great introductory book. Also read about grid systems and gestalt psychology.
Good luck!