Really, really easy autocomplete with jQuery + jQuery tmpl

autocomplete.js

/*
 * what's happening here?
 *
 * 1) define and pre-compile our template that our results should be rendered as
 * 2) bind to the keydown event of the input#search text box
 * 3) define our callback, to pull json search results every time we're executed
 * 4) define a callback for receiving our json data, which does:
 *    a) remove all previous search results (<h3> tags)
 *    b) append our new search results to our div#results
 *
 * XXX: Needs limits and pagination.
 */

$(document).ready(function() {
  $.template('resultsTemplate', '<h3><a href = "{{= $data}}">{{= $data}}</a></h3>');

  $('#search').live('keydown', function() {
    $.getJSON'/path/to/search, { 'search': $('#search').val() }, function(data) {
      $('h3').remove();
      $.tmpl('resultsTemplate', data).appendTo('#results');
    });
  });
});