Google Apps now allows you to delegate access to your My Contacts group within your Gmail contacts, without granting access to your email or other data in your Google Apps account.
To do so, go to More > Contacts on your Google Apps menu bar:
Click More > Manage Delegation Settings within Google Contacts:
You can only share the contents of your My Contacts group within your Contacts (other groups, or subsets of your My Contacts group, can’t be shared).
Share your My Contacts group with whomever you choose; delegation is limited to Boise State’s Google Apps domains, which means employees can only delegate Contacts access to other employees, and students can only delegate Contacts access to other students. Also, delegation is limited to no more than 25 individuals.
People you choose to share with will receive an email notification, and must follow the instructions in the email in order to view the shared Contacts.