Just use jQuery's .die() method in the handler:
Example: http://jsfiddle.net/Agzar/
$('a.remove_item').live('click',function(e) {
alert('clicked');
$('a.remove_item').die('click'); // This removes the .live() functionality
});
EDIT:
Or if you only wanted to disable the event on a per-element basis, you could just change the class name since live() is selector-based.
Example: http://jsfiddle.net/Agzar/1/
$('a.remove_item').live('click',function(e) {
alert('i was clicked');
$(this).toggleClass('remove_item remove_item_clicked');
});
This changed the class from remove_item to remove_item_clicked which could have the same styling. Now live() will not fire after the first click.