Not sure how advanced you are, but as a relative noob, I've been reading, among others, the following sites:

http://www.smashingmagazine.com/ http://uxmagazine.com/

Smashing has really good books, most if not all you can buy as ebooks. If you want a good overall primer for less advanced UI/UX designers, read the Smashing Book #1

I also follow people like Paul Irish, but that's more for HTML5/CSS3 and front-end dev...