Special thanks to Florian Schoppmann for bringing this issue to the community's attention. I'm extracting the steps to get Address Book and Mail to read from the Stanford LDAP directory. General instructions for setup can be found here:
Since Address Book in 10.6 does not allow for self-signed certificates, you will need to take the following steps to get it working:
1. Retrieve the certificate by going to Terminal and typing:
openssl s_client -connect mothra.win.stanford.edu:636
2. Copy everything in between
"-----END CERTIFICATE-----" (including these lines)
to a new file with suffix .pem
3. double click on the file you just saved (
4. double click on the new certificate, click on the 'Trust' disclosure triangle and set "When using this Certificate:" to "Always trust".
As Florian says, Voilà!