Make sure to subscribe to the dev list and follow all of the JIRA traffic there if you want to be ontop of the latest and greatest. <t:dataTable> and related components like t:columns are changing almost daily (for the better.)
For this feature see: http://issues.apache.org/jira/browse/MYFACES-175 See also: http://issues.apache.org/jira/browse/MYFACES-343 sean
