A while ago, I posted a blog about the SPA942 Personal Directory. Well I've built on it a bit now and managed to get it populated from the information taken out of our LDAP server (Microsoft Active Directory).
When we allocate a phone to someone, we fill in the ipphone field with their extension. We then also add two other ipphone entries, the first being the MAC address of the phone, the second being the phone's IP.
I'm also managing calling groups (queues) in LDAP by creating security groups...