Logons and XP Pro

I am on the technology committee for my son’s school. We are trying to determine if it is possible to set-up XP Pro so that each student can logon to any computer under Win2K server. I see that you can force a domain type of logon screen. Can XP be set-up to logon to the server first or will it force the creation of a user account on each computer? We have 4 classes of about 25 students each and will purchase 30 computers for a lab set-up.