jquery.color.js

/*
 * jQuery Color Animations
 * Copyright 2007 John Resig
 * Released under the MIT and GPL licenses.
 */

(function(jQuery){

	// We override the animation for all of these color styles
	jQuery.each(['backgroundColor', 'borderBottomColor', 'borderLeftColor', 'borderRightColor', 'borderTopColor', 'color', 'outlineColor'], function(i,attr){
		jQuery.fx.step[attr] = function(fx){
			if ( fx.state == 0 ) {
				fx.start = getColor( fx.elem, attr );
				fx.end = getRGB( fx.end );
			}

			fx.elem.style[attr] = "rgb(" + [
				Math.max(Math.min( parseInt((fx.pos * (fx.end[0] - fx.start[0])) + fx.start[0]), 255), 0),
				Math.max(Math.min( parseInt((fx.pos * (fx.end[1] - fx.start[1])) + fx.start[1]), 255), 0),
				Math.max(Math.min( parseInt((fx.pos * (fx.end[2] - fx.start[2])) + fx.start[2]), 255), 0)
			].join(",") + ")";
		}
	});

	// Color Conversion functions from highlightFade
	// By Blair Mitchelmore
	// http://jquery.offput.ca/highlightFade/

	// Parse strings looking for color tuples [255,255,255]
	function getRGB(color) {
		var result;

		// Check if we're already dealing with an array of colors
		if ( color && color.constructor == Array && color.length == 3 )
			return color;

		// Look for rgb(num,num,num)
		if (result = /rgb\(\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*\)/.exec(color))
			return [parseInt(result[1]), parseInt(result[2]), parseInt(result[3])];

		// Look for rgb(num%,num%,num%)
		if (result = /rgb\(\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*\)/.exec(color))
			return [parseFloat(result[1])*2.55, parseFloat(result[2])*2.55, parseFloat(result[3])*2.55];

		// Look for #a0b1c2
		if (result = /#([a-fA-F0-9]{2})([a-fA-F0-9]{2})([a-fA-F0-9]{2})/.exec(color))
			return [parseInt(result[1],16), parseInt(result[2],16), parseInt(result[3],16)];

		// Look for #fff
		if (result = /#([a-fA-F0-9])([a-fA-F0-9])([a-fA-F0-9])/.exec(color))
			return [parseInt(result[1]+result[1],16), parseInt(result[2]+result[2],16), parseInt(result[3]+result[3],16)];

		// Otherwise, we're most likely dealing with a named color
		return colors[jQuery.trim(color).toLowerCase()];
	}
	
	function getColor(elem, attr) {
		var color;

		do {
			color = jQuery.curCSS(elem, attr);

			// Keep going until we find an element that has color, or we hit the body
			if ( color != '' && color != 'transparent' || jQuery.nodeName(elem, "body") )
				break; 

			attr = "backgroundColor";
		} while ( elem = elem.parentNode );

		return getRGB(color);
	};
	
})(jQuery);

jquery.random-color-change.js

jQuery.fn.extend({
colorChange: function(speed) {
	if (!speed){speed = 4000;}
	return this.each(function() {
		function colorizer()
		{
			var color = 'rgb(' + (Math.floor(Math.random() * 256)) + ',' + (Math.floor(Math.random() * 256)) + ',' + (Math.floor(Math.random() * 256)) + ')';
			return color;
		}
	jQuery(this).animate({backgroundColor: colorizer()}, speed, function() {jQuery(this).colorChange()})});}

});

http://patrickdevivo.com/jquery-color-change/