We have a OS X server where all of our users are stored and set up. Currently, when a user goes to a computer in our school, every user comes up at the login screen so they can choose who they are and log in.

We just got new iMac's and I cannot figure out how to get the login part set up the same way. I need it to list all of the users available but it will only list the admin of the computer.

Have you joined the new computers to the Open Directory (or Active Directory, whichever you're running on the server)?

i do not believe i have done that. i dont think i know how to. any pointers on how to do that?

http://www.computerworld.com/s/article/9016687/How_to_Understanding_Mac_OS_X_Open_Directory

Google has many more suggestions on "Mac OS X how to join open directory".