Besides the fact that only IE7+ supports it, why would you use something such as this example? Namely:
<select>
<option label="Volvo">Volvo (Latin for "I roll")</option>
<option label="Saab">Saab (Swedish Aeroplane AB)</option>
</select>
After all, ‘Latin for “I roll”‘ and ‘Swedish Aeroplane AB’ are lost (i.e., only remain in the source code).
In that example, the long text will be sent to the server when the form is submitted.
Given the existence of the value attribute, it is redundant.