Should we put <input> inside <label>?

Question

I saw 2 different method on same form example:

on http://www.alistapart.com/articles/prettyaccessibleforms/ why they are using 2 method in first fieldset they are keeping input after labeland in 2nd fieldset they are keeping input after label. Why?

<fieldset>
  <legend>Delivery Details</legend>
  <ol>
    <li>
      <label for="name">Name<em>*</em></label>
      <input id="name" />
    </li>
    <li>
      <label for="address1">Address<em>*</em></label>
      <input id="address1" />
    </li>
    <li>
      <label for="address2">Address 2</label>
      <input id="address2" />
    </li>
    <li>
      <label for="town-city">Town/City</label>
      <input id="town-city" />
    </li>
    <li>
      <label for="county">County<em>*</em></label>
      <input id="county" />
    </li>
    <li>
      <label for="postcode">Postcode<em>*</em></label>
      <input id="postcode" />
    </li>
    <li>
      <fieldset>
        <legend>Is this address also your invoice »
address?<em>*</em></legend>
        <label><input type="radio" »
name="invoice-address" /> Yes</label>
        <label><input type="radio" »
name="invoice-address" /> No</label>
      </fieldset>
    </li>
  </ol>
</fieldset>

why they are sometime keeping input after label and sometime inside?

Update:

here http://www.usability.com.au/resources/forms.cfm they are also keeping input after label not inside

Answer 1

This is according to the specs, and works in all modern browsers (but not in IE6 - clicking the label will not set focus to the input control, unless you include an id and for):

  <label>
      Name: <input type="textbox" name="firstName" />
  </label>

As for "why" - In the <fieldset>, the radio buttons were put in the labels so there won't be an unclickable gap between the label and its radio button.