I recently got my packet of 50 RGB LEDs, and free 50 current-limiting resistors to go along with it, direct from China. 

It was called "50x 5mm RGB LED Slow Colour Change Free Resistors", and the seller is "amigoofchina". You can see his eBay Store here.

In the picture, I have a close-up of one of the LEDs, and a row of them in the process of changing colors. They don't keep time very well, they just dance to their own drum.

Check out the video of a bunch of them in action, and a great explaination at Dan's Data: The Embarassingly Easy Case Mod.