Create a color meta field

Colorpicker Metafield

function __construct() {
		add_action( 'admin_enqueue_scripts', array(&$this,'em_enqueue_color_picker' ));
		add_action('admin_head', array(&$this,'add_colorpicker_script')); 
	}

function em_enqueue_color_picker( $hook_suffix ) {
      // first check that $hook_suffix is appropriate for your admin page
	    wp_enqueue_style( 'wp-color-picker' );
	   	wp_enqueue_script( 'wp-color-picker' , false, true );
	}

 
	function add_colorpicker_script() {  
	    global  $post;  
	    $custom_meta_fields = $this->your_meta_fields_function(); //where you meta_fields are defined
	      
	    $output = '<script type="text/javascript"> 
	                jQuery(function() {';  
	                  
	    foreach ($custom_meta_fields as $field) { // loop through the fields looking for certain color type 
	        if($field['type'] == 'color')  
	            $output .= 'jQuery(".colorpicker").wpColorPicker();';  
	    }  
	      
	    $output .= '}); 
	        </script>';  
	          
	    echo $output;  
	}