Cymbolism - quantifying association between colors and words
cymbolism.com
cymbolism.com
This site looks to have set up a nice data gathering method, they are not pioneers in the field though, as lots of work on the subject exists already, but more won't hurt.
Some things I recall -
red & yellow - can induce hunger (McDonalds)
blue - calming, trust
green - peace, calming (nature)
Another thing I recall reading is that people are more trusting of websites with white backgrounds. Though this could simply stem from the fact that the majority of 'major' websites people are familiar with have white backgrounds.
Except, of course, for synesthetes: