Color Picker is a simple tool to let you select any color you see on your computer's screen. It will provide that color data to you in red, green, and blue values or in an HTML hex format for easy copying into your site's CSS code.

It does not do anything else. It doesn't hide in your system tray, it doesn't have any options or parameters. It doesn't let you adjust the color after you've picked it. It just lets you pick the color from the screen and gives you the values necessary to use that color somewhere.