jQuery.noConflict()

<script type="text/javascript" src="other_lib.js"></script>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
  $.noConflict();
  // Code that uses other library's $ can follow here.
</script>

<script type="text/javascript" src="other_lib.js"></script>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
  $.noConflict();
  jQuery(document).ready(function($) {
    // Code that uses jQuery's $ can follow here.
  });
  // Code that uses other library's $ can follow here.
</script>

jQuery.noConflict();
// Do something with jQuery
jQuery("div p").hide();
// Do something with another library's $()
$("content").style.display = 'none';

jQuery.noConflict();
(function($) { 
  $(function() {
    // more code using $ as alias to jQuery
  });
})(jQuery);
// other code using $ as an alias to the other library

jQuery.noConflict()(function(){
    // code using jQuery
}); 
// other code using $ as an alias to the other library

var j = jQuery.noConflict();
// Do something with jQuery
j("div p").hide();
// Do something with another library's $()
$("content").style.display = 'none';

var dom = {};
dom.query = jQuery.noConflict(true);

// Do something with the new jQuery
dom.query("div p").hide();
// Do something with another library's $()
$("content").style.display = 'none';
// Do something with another version of jQuery
jQuery("div > p").hide();