Okay...here goes:
1.) Make sure that they are set to logon to a domain. Go to your network properties, click on "client for microsoft network" and hit properties. There will be a check box there asking if you want this machine to logon to a domain. Check the box and enter in the name of the domain in the place provided. Reboot.
2.) When the logon screen comes up, it will have an extra field called domain. So now, you are using NT domain accounts to logon just as if you were using win2k or nt for clients.
3.) The next thing you want to do is create a batch file that is set to run everytime a user logs in. A batch file is basically just DOS commands that are executed in order when the batch file is run. For instance, if you want every user to login and get a mapped drive to your file server's D:\ drive, then the command would look somethign like this: "net use x: \\servername\D:" Put that command in a file and name it "something.bat"
4.) After you have your batch file, you need to make the domain controller know to run it everytime a user logs in. In an NT server, there is a default share called NETLOGON that points to a path on the server. I believe the path is c:\winnt\system32\Rep\Imports\Scripts. If you put this batch file in that directory on the domain controller, the client machines will automatically look there for a file to run at startup.
5.) The next and final step is to have all user accounts specify the name of the file you wish to run at login. These accounts already know to look at the share NETLOGON (which is actually mapped on the server to c:\winnt\system32\Rep\Imports\Scripts). So, if the account is going to look there automatically, you have to tell it what file to look for in that directory. To do this, go to your domain controller, pull up the "user manager for domains," and go to the properties for all your users one at a time. In the properties there will be a section called "profile." Go to that section and you will see a field called login script. That is where you want to put the name of the batch file you created. So, everytime that user logs in, his machine automatically looks to the NETLOGON share and looks for a file that you specified in there profile options. If it finds the file, then it will run it and you will have mapped drives.
Hope this helps...good luck