I have found that the Colorzilla add-on for Firefox is a super helpful tool to have. This is one of the first add-ons that I download for my browser. It is especially helpful for Photoshop or PSP users who see a color on website but don't know what the HEX code is for it. You can easily find it by having Colorzilla installed. You get a section in your bottom bar of your browser that looks like the image to the right.
All you have to do is click the color and you get a dropper, hang it over the color on the web page you want to see and presto! You can now use that color in your work. You can get the add-on here.