Before version 1.8, Google Apps Sync for Microsoft Outlook did not support automatic updating of your domain's Global Address List (GAL). Domain administrators were forced to creating a static copy of the GAL and make that available to Outlook via a change in the desktop's registry. With the latest version, the GAL will be kept up to date automatically, and be made available to Outlook for searching or offline use. This is a big step forward for making Google Apps usable in enterprise environments. If you're a domain administrator that previously rolled out the registry changes to your workstations, be prepared to back out those changes in order for the new dynamic GAL to be supported.
On a side note, Google Apps Sync for Microsoft Outlook is supposed to upgrade automatically (although a reboot is necessary in Windows XP). For some reason, my version seems to be stuck at 1.7.318.115 and no automatic updating seems to be happening.