I like to play around with GIMP (…ok, I’m addicted) and ran into a few situations making custom palettes where I need to convert a bunch of hexadecimal colors to their RGB equivalents. I figured a quick search would yield plenty of batch hex-to-RGB solutions. Not so. I finally found Zonum Solutions Color Converter where I can batch convert between RGB to HEX and vice-versa. This little gem save a ton of time and is forever bookmarked.
Check out Color Converter at http://www.zonums.com/online/color_converter/
They have a bunch of other tools including Color Ramp that creates color-ramp lists for your data and maps. Works great to create simple palettes and gradients too.
For more complex gradients, I use an online Photoshop-like CSS gradient editor from ColorZilla called Ultimate CSS Gradient Generator. The CSS is a simple cut and paste with endless possibilities. The most recent updates include support for radial and diagonal linear gradients, full multi-stop gradients in Internet Explorer 9 (IE9) using SVG, Sass SCSS format using Compass mixins (needs latest beta of Compass), copy to clipboard button for quickly grabbing the generated code, and easy resizing of preview panel by dragging its corner. And it’s FREE! Happy Happy Joy Joy!
Check out Ultimate CSS Gradient Generator at http://www.colorzilla.com/gradient-editor/