MySQL - copy data from one column to another in the same table

I have a table as shown below, how can I copy the contents from itemName to itemDescb
I need to copy from one column to another column in the same table.


CREATE TABLE `products` (
  `PID` int(11) NOT NULL auto_increment,
  `prodcode` varchar(10) default NULL,
  `cat` varchar(40) NOT NULL default '',
  `subcat` varchar(40) default NULL,
  `itemName` varchar(50) default NULL,
  `itemDesc` text,
  `itemDescb` varchar(40) default NULL,
  `itemPrice` decimal(6,2) default '0.00',
  `special` decimal(6,2) default NULL,
  PRIMARY KEY  (`PID`),
  UNIQUE KEY `id` (`PID`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=10 ;

Thanks in advance for your help.