Make sure to call your scripts after the DOM is finished loading e.g.,
$(document).ready(function() {
$(".my_color").spectrum({
color: "#f00"
});
});
Works fine with the correct execution order: http://jsfiddle.net/xqdBd/
Notice how this: http://jsfiddle.net/xqdBd/1/ doesn't work anymore as the JavaScript is called before the DOM has finished loading.
Another problem is here:
<link rel="stylesheet" type="text/css" href="spectrum.css ">
Notice the extra space at the end of "spectrum.css "
, that or your JavaScript files aren't being loaded. Without seeing the page you are using it is impossible to tell.