Typing into combobox should narrow down the list if the AutoExpand property is enabled. Yes, the ID is the value saved but users should not see it. They start typing last name and the AutoExpand should show only records in the list that match the user input.
Adding new records into a lookup table 'on-the-fly' is what the combobox (or listbox) NotInList event is for. http://www.blueclaw-db.com/access_no...ed_example.htm