The official press release of Samba 4 can be found on the Samba website.
In short, you can join a Windows (all recent releases should be supported) machine to a Samba Active Directory, and it will behave much as it does in AD, including Kerberos domain logins where applicable. Samba 4 is now at a point where it can begin replacing existing production deployments, and users are encouraged to try out Samba 4 in a test environment before implementing it in a work environment!
Samba as a Active Directory Domain Controller
Here you can find everything to setup a Samba Active Directory Domain Controller and all that is related to this topic.
- Samba Active Directory HOWTO: Contains everything for setting up a basic Samba Active Directory Controller
- Migrating a Samba 3 PDC to a Samba Active Directory Domain Controller: If you are running a Samba 3 NT4-style environment and want to move to Active Directory, this is the documentation that contains all the necessary information
- Beyond Samba: Connecting other Services/Daemons to your Samba Active Directory (e. g. authentication, etc.)
Samba as a Domain Member Server
General Documentation on Samba
- v4-0-test (replaced by master)
- v4-0-stable (current branch for 4.x.x releases)
- master (current Samba development) branches
- For more info on available branches, as well how to obtain the sources via a Git client, see the samba.org devel page.
Historical Documentation on the Development of Samba4
- Franky: A Hybrid Samba Active Directory Controller (outdated!)