Before Adding user make sure that User is already available in Windows Server 2003 - "Active directory users and computers"

Ok, lets take a quick overview on adding User Group to Active Directory in Windows Server 2003.

Step 1: Start Menu - Control Pannel - Administrative Tools and in it Active directory users and computers.

Step 2: Drill the Active Directory User and Computers and in it select the server, example on my PC i have named server as "MyServer" so need to drill "MyServer"
- And Expand Users directory

Step 3: Right Click user directory and select New from popup menu and click user, to create new user.

Create New User

Choose Password Expiration policy for newly created user.

Finally New User is created.

And you are done creating user. Note: You have created user in windows server 2003.  Creating uer in windows server 2003, doesn't allow user to access sharepoint site.  We need to assign proper permission to user in order to allow him access to sharepoint site.  Please refer my next article in which i have explained how to create user in sharepoint and assign proper permission.