Visit kuler.adobe.com to view thousands of color themes created by a huge community of users. Create and contribute your own color themes, and download themes that you like as Adobe Swatch Exchange files for easy use in InDesign, Illustrator or Photoshop.
The interface used in Kuler to create new color themes is similar to the new Live Color feature in Illustrator CS3, which lets you create a color and then quickly find complementary colors, split complements, analogous colors, etc.
Illustrator CS3 communicates directly with Kuler via the new Kuler palette (found in Window > Adobe Labs > Kuler) in Illustrator.
Mac users can download the Kuler Dashboard Widget from the Kuler web site for another easy way to quickly access Kuler.