Given a field for Content Profile for a user, how can I extract that field via code?
You'll have to load the content profile node into a variable first using content_profile_load.

This should work:

$user_profile = content_profile_load('profile', $user-&gt;uid);


That will return an object ($user_profile) that you can call the fields which you've set up.
Use 

echo '&lt;pre&gt;'.print_r($user_profile,1).'&lt;/pre&gt;';


to see which fields are available.