This Colour Palette Generator is awesome. Insert the URL of an image to get a colour palette to match the photo.
colr.org lets you play around with the colour schemes in images with tags
Colour Lovers is an online community for people to share and discuss colour palettes, patterns and colour articles. Over 2,103,949 user-created seamless patterns to use in your creative projects.
Tag Galaxy is an interactive way to find photographs through tags on Flickr.