Views3 - Is there are feature in Views3 that allows for authenticated users to change the fields in a view?
you can allow users acces to the views UI but you couldn't limit that just to "fields". It wouldn't be end user friendly either.

You might want to show all fields in your view and then hide the fields dynamically with css.

If you want it more robust you can use a hook like hook_views_post_execute to remove fields dynamically.