<input type="checkbox" name="lala" value="1" checked="checked" />
<input type="checkbox" name="blah" value="2" />
<button onclick="getData();">Получить</button>
<script src="http://code.jquery.com/jquery.min.js" type="text/javascript"></script>
<script>
    function getData() {
       var arr = jQuery('input[type="checkbox"]:checked').serializeArray();
       var out = {};
       for( var i = 0; i < arr.length; i++ ) {
           out[ arr[ i ].name ] = arr[ i ].value;
       }

       alert( JSON.stringify( out ) );
   }
</script>