There probably is a complicated way to use autofs and push the commands to the clients, but a simpler way might be to use the managed preferences in Workgroup Manager on the server.
Open WGM. Select a user or group to manage from the list. Select the Preferences button at the top.
Selet the "Login" icon in the list of manageable preferences. Select "Items" from the row of tabs across the top.
Drag a shared folder into this window that you want the clients to mount at login.
This should behave just like putting a mounted volume in the login items in the client's System Prefs > Accounts > Login Items. Haven't actually tested it, mind you.
Autofs could make the share more persistent and can mount a share at almost any location in the file system, but managed prefs should do what you want.