Question

What is the time frame for the global address book to be updated and how is this accomplished when adding a new user to active directory?

Global Address List, Active Directory, Windows Server 2003

what is the time frame for the global address book to be updated and how is this accomplished when adding a new user to active directory? I usually add a new user one day and it does not show up until sometime the next day

Could be you/your users are looking at offline address book, by default, it is only regenerated once every 24 hours. It is possible your RUS is not running, though, or is misconfigured. If you shut down a domain controller or Exchange server that the RUS was using. Here is a good article about the RUS and somethings to check.
http://www.msexchange.org/tutorials/MF017.html