Checkboxes

    <label>
        Checkbox right
        <input type="checkbox">
        <span class="icon-checkbox"></span>        
    </label>
    <label>
        <input type="checkbox">
        <span class="icon-checkbox"></span>
        Checkbox left
    </label>
    <label>
        Checkbox right (cross as marker)
        <input type="checkbox">
        <span class="icon-checkbox cross"></span>
    </label>
    <label>
        <input type="checkbox">
        <span class="icon-checkbox cross"></span>
        Checkbox left (cross as marker)
    </label>

Radio buttons

    <label>
        Radio button right
        <input name="ra-test" type="radio">
        <span class="icon-radio"></span>
    </label>
    <label>
        <input name="ra-test" type="radio">
        <span class="icon-radio"></span>
        Radio button left
    </label>

Labels containing block elements

Fake label on a radio button

Fake label on a checkbox

  <!-- radio button with real label -->
  <label>
    <input name="ra-test" type="radio">
    <span class="icon-radio"></span>
    Real label on a radio button for direct comparison
  </label>

  <!-- radio button with fake label -->
  <div class="pseudo-label-box">
    <label>
      <input name="ra-test" type="radio">
     <span class="icon-radio"></span>
    </label>
    <div class="label-box">
      <div class="label-content clear">
        <p>Fake label on a radio button</p>
      </div>
    </div>
  </div>

  <!-- checkbox with real label -->
  <label>
    <input name="ra-test" type="checkbox">
    <span class="icon-checkbox"></span>
    Real label on a checkbox for direct comparison
  </label>

  <!-- checkbox with fake label -->
  <div class="pseudo-label-box">
    <label>
      <input name="ra-test" type="checkbox">
     <span class="icon-checkbox"></span>
    </label>
    <div class="label-box">
      <div class="label-content clear">
        <p>Fake label on a checkbox</p>
      </div>
    </div>
  </div>

Fake labels require some JavaScript to function:

    $('.pseudo-label-box').on('click', function() {
        $(this).find('input:radio, input:checkbox').first()[0].checked = true;
    });