How do I implement JQuery.noConflict() ?

jQuery.noConflict will reset the $ variable so it's no longer an alias of jQuery. Aside from just calling it once, there's not much else you really need to do. Though, you can create your own alias with the return value, if you'd like:

var jq = jQuery.noConflict();

And, generally, you want to do this right after including jQuery and any plugins:

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

You can also go one step further and free up jQuery with noConflict(true). Though, if you take this route, you'll definitely want an alias as neither $ nor jQuery will probably be what you want:

var jq = jQuery.noConflict(true);

I think this last option is mostly used for mixing versions of jQuery, particularly for out-dated plugins when you want to update jQuery itself:

<script type="text/javascript" src="jquery-1.4.4.js"></script>
<script type="text/javascript" src="jquery-older-plugin.js"></script>
<script type="text/javascript">
    var jq144 = jQuery.noConflict(true);
</script>
<script type="text/javascript" src="jquery-1.6.4.js"></script>
<script type="text/javascript" src="jquery-newer-plugin.js"></script>

By default, jquery uses the variable jQuery and the $ is used for your convenience. If you want to avoid conflicts, a good way is to encapsulate jQuery like so:

(function($){

    $(function(){

        alert('$ is safe!');

    });

})(jQuery)