See http://foliotek.github.com/AjaxQ for a demonstration and documentation

$.ajaxq follows the $.ajax options and return value, with an extra first parameter (the queue name).

  $.ajaxq(name, opts);

$.getq follows the $.get options and return value, with an extra first parameter (the queue name).

  $.getq(name, opts);

$.postq follows the $.post options and return value, with an extra first parameter (the queue name).

  $.postq(name, opts);

$.ajaxq.isRunning returns a boolean representing if any requests are currently running. qname is an optional parameter.

  $.ajaxq.isRunning(qname);

$.ajaxq.getActiveRequest returns the currently processing jqXHR for the given queue. qname is required.

  $.ajaxq.getActiveRequest(qname);

$.ajaxq.clear removes any unprocessed requests from the queue. qname is an optional parameter.

   $.ajaxq.clear(qname);

$.ajaxq.abort aborts the current request, and removes any unprocessed reqeusts from the queue. qname is required.

  $.ajaxq.abort(qname);

http://foliotek.github.com/AjaxQ#demo