One of the reasons we use Windows in the office at work is Active Directory. It makes it a piece of cake to bring up a new workstation and have a new or existing user login and do their work. Once all the Applications are installed, a user can login on any workstation and have all their documents and settings available to them.
Is there any way of doing this on Ubuntu?
Sure, there are syncing programs like Ubuntu One that sync the files (and hopefully eventually settings), but as far as I am aware it still requires each workstation the user wishes to log onto to already have their user account set. Also, any time a user changes their password it needs to be changed on each machine the user logs into.
It would also be useful if this applied to servers as well, so a user can SSH into a server and have the same files as on their desktop in their home directory.
Does this sort of ability existing in Ubuntu currently?
You can use OpenLDAP for authentication and nfs in combination with automount for mounting their home directory to the desktop.
Another possibility is to use the LTSP server project to run all the application from a server and run only thin clients. Which solution is the best, depends on your particular requirements.
Ubuntu also has the Likewise client, which is not just like Active Directory but is an Active Directory client, so you can use your Windows domain logins on Ubuntu.
OpenLDAP or Fedora Directory Services will provide you with what your looking for. FDS gives you a nice interface by default iirc. However, this will work well for Linux, *BSD and OSX systems. As far as I know, windows systems will not by default ( ie without adding software ) Authenticate against OpenLDAP so if you have a a mixed environment you would essentially need to run 2 servers. I believe it's possible to sync openldap/fds with AD however I've never tried it.
The Likewise client will auth against AD directly however since AD is only really concerned with windows you will probably sacrifice some of the functionality that you would otherwise get with openldap/fds. YMMV.