A quick Google search shows that Apple.com has the process documented.
Log in as an administrator to follow these steps. The first user account created in OS X Lion is an administrator account.
To configure for Active Directory
Add the Active Directory server to the list of DNS server:
1. Open System Preferences, choose Apple menu > System Preferences…
2. Choose View > Network.
3. If the padlock in the lower left is locked, click it and enter an administrator name and password to unlock.
4. Enter "DNS" in the search field and press return.
5. Click "+" under the "DNS servers:" pane, enter IP address of the Active Directory server.
6. Click "+" under the "Search Domains:" pane, enter Active Directory domain name.
Bind to Active Directory server through Users & Groups pane:
- Open System Preferences, choose Apple menu > System Preferences…
- Choose View > Users & Groups.
- If the icon in the lower left is locked, click it and enter an administrator name and password to unlock.
- Click "Login Options".
- Click "Join…" button next to "Network Account Server:".
- Enter the hostname of the Active Directory server, then click OK.
- Enter credentials for the Active Directory server.
Execute the following Terminal command to enable the CUPS web interface:
cupsctl WebInterface=yes
Open the URL http://localhost:631/printers
in Safari.
For each printer you wish to share using Kerberos:
1. Click the printer name in the list.
2. Choose "Set Default Options" from the "Administration" pop-up menu.
3. Click "Policies".
4. Choose "kerberos" from the "Operation Policy:" pop-up menu.
5. Click "Set Default Options".
Once you have completed this process, run this command in Terminal:
cupsctl WebInterface=no