New Server: How do we aim ALL users email accounts to use the new addresses

Question

We have a new server which we are using for mail (incl. smtp), we need to be able to make it so when a user logs in and loads mail (just like they would have done before) it finds their new email account as seamlessly as possible.
In a windows environment (*i know i heard the groan before i said it but thats the system i know*) i know exchange would force all of the new settings through to each user remotely. Does apple have a solution like this or are we really going to have to login as each user and setup their accounts for them. This would take literally weeks.
I'm pretty sure there is a way to do this, but i couldn't find any previous posts about it.... hope this is in the right place edit:now and i will be extremely grateful to anyone who can help me with this issue.
Other Info: Mac OSX server environment with approx 260 Macs on Tiger, Mail version 2.1 and over 900 users. 100 of whom have been transferred manually by setting the accounts up and entering settings in each of the users mail applications. each user is using roaming profiles so when it's done once it's done over the entire network.

Answer 1

Thanks for the feedback am trying to work on a script now but can't get enough info about applescript, There is a setting in workgroup manager which says email when it is activated and we type in the users email address it should be feeding through from the next logon. This isnt the case for some reason.
All mail is backed up and ready to reinstate if necessary, our other problem with documentation or any kind of user input is that we are a primary school with an entirely MAC network with only two technical support and i was based from a windows background...... *** to be us at the moment. lol
If this was exchange we'd just link to Active directory and be done with it.......
Thank you for your responses i can't seem to say anyone was helpful at the moment site error.... any more ideas will be gladly accepted. (goes off hunting for more applescript documentation)
(does anyone know how to make applescript echo the username back to itself and then set it as a variable? then i need to combine it so something like this....
set theEmailAddress to {echoedresponse, "@thisemailaddress.com"}
that at least would let me set the script to work with only a little input from the user....... i hope infants can type two letters correctly if they are starred out.