Design is an evolving discipline and practice. There are many good books, journals, websites and blogs covering user-centred design topics at all levels. Here is a short list of books and links to get you started.

The Design of Everyday Things

Donald A Norman (Basic Books, 2002)

Serious Play: How the World's Best Companies Simulate to Innovate

Michael Schrage (Harvard Business Press, 1999)

Letting Go of the Words: Writing Web Content that Works

Janice (Ginny) Redish (Morgan Kaufmann, 2007)

Don't Make Me Think: A Common Sense Approach to Web Usability

Steve Krug (New Riders Press, 2nd edition, 2000)

Cost-Justifying Usability

Randolph G. Bias, Deborah J. Mayhew, (Morgan Kaufmann, 1994) - Design Council, UK - American Institute of Graphic Arts - Design Management Institute (USA)