Hexdecimal is a small application that gives you a simple way to capture any colour on-screen, and later convert it to a hexidecimal colour chain. You can also modify the RGB, HSL and CMYK values of any colour, and create and save colour palettes via a simple interface, where you only have to signal and click.
The colours can be copied into a large variety of formats including #RRGGBB and 0xRRGGBB as default. The Hexidecimal program is designed to consume the least resources possible, and can be installed and uninstalled easily. Simple, effective and completely free.