We use a CentOS based LDAP Directory Server at work to authenticate Windows (XP, Vista, 64 & 32 bit) systems as well as Linux clients (Fedora 10-12) to the network and SMB shares.
Instructions for integrating Samba into the Directory Server, go here
If you are looking to make your LDAP server authenticate Windows clients as if they were joining a Windows Domain, then follow this guide
. I didn't write that guide, but I have done some work based on it.
As I said, we use it at work, but do not use anything like network homes for Windows users or running login scripts. If you have a good understanding of Samba, that should not be too hard to manage.
The Directory Server is a good tool to know. If you search on the internet, you will find that you can also control SUDO access and NFS based home folders with it.
Good Luck! Let me know if you have any problems.