Colorpicking
Ladyada writes

Here is an example of how to make a cool Internet application using the XPort shield I recently released. This is very simple, but its a good example of getting and outputting data. Basically the Arduino serves up a webpage with a bunch of nice javascript code that allows you to select a color. It also displays a “current color” (in this case a light green).

Ledcolorpickerhard T
When you click “Submit” on the page, another request is made to the XPort/Arduino, this time with a GET command ?color=#xxxxxx with the color information. The Arduino looks for this command, parses the color requested and calls analogWrite() on the three LEDs to change them into that color.