University of Pennsylvania’s Positive Psychology Center

Prof. Murray Seligman is, without doubt, one of the leaders and founders of contemporary Positive Psychology. This website contains a number of good resources, including papers and interviews.
TED.com Thoughtful, Innovative and Exciting.

To me, TED.com is the pick of the litter. Go to this site, and you’ll have access to video lectures from innovative thinkers all over the map. I watch a lecture with my son every night.