MySQL: Updating ID auto_increment fields

howdy, this should be simple but i don't know it. i use the following mysql table field as the Key for my tables: "id int(10) unsigned NOT NULL auto_increment," now, when i have to clean up items in my tables, like when users have sent off a .html form multiple times and i want to delete duplicate submissions, how can i quickly & easily update all of the 'id' fields in the entire table, to reflect the numeration change? now, using phpmyadmin, if i go in and delete a few entries, the id's have gaps in them.. mucho gracias, tom