Pantone, "where color comes from", has a very interesting site with various in-depth reports on color. I visited the Fashion & Home section, and had fun reading the various trend reports and viewing the upcoming color pallets.
Another color-related site, but a little on the lighter side is Colorstrology. I stumbled upon it via Pantone's site since they are the sponsor of the horoscope-style site that gives your "personal color" that corresponds to your birthday.