You can get the target of the event using event.target.

$('input:checkbox[id]').change(function(event) {
  var checkboxID = $(event.target).attr('id');
  alert(checkboxID);
});

JSfiddle Demo

If this points to your checkbox, then you would get the id using $(this).attr('id')

For example:

$('input:checkbox').click(function(){
    var id = $(this).attr('id');
    // do something with id
});

See DEMO.