Dear Sir,
I will like to setup a ldap server for my email server(sendmail, running on redhat 9) to share Global Address Book, can anyone give me some guide how to do this?

you can try this guide
http://www.iconimaging.net/~jradford...mail-ldap.html

Thank Mrcheeks
I had follow your instruction to install the openldap,
1. i downloaded openldap 2.2.24 which is the stable version,

2. after i run ./configure, it show this error checking for
Berkeley DB link (default)... no
checking for Berkeley DB link (-ldb43)... no
checking for Berkeley DB link (-ldb-43)... no
checking for Berkeley DB link (-ldb-4.3)... no
checking for Berkeley DB link (-ldb-4-3)... no
checking for Berkeley DB link (-ldb42)... no
checking for Berkeley DB link (-ldb-42)... no
checking for Berkeley DB link (-ldb-4.2)... no
checking for Berkeley DB link (-ldb-4-2)... no
checking for Berkeley DB link (-ldb-4)... no
checking for Berkeley DB link (-ldb4)... no
checking for Berkeley DB link (-ldb)... yes
checking for Berkeley DB version match... yes
checking for Berkeley DB thread support...
yes checking Berkeley DB version for BDB backend... no configure: error: BDB/HDB: BerkeleyDB version incompatible

3. then i download & install the db-4.2.52.NC & also try db-4.3.27 , it still given me the same error.
any idea how to slove this?

please check your BerkeleyDB version.