to map a drive at logon, you can do one of the following... this is based on 1 of 2 things. You are using AD to manage your accounts, or you are doing this only from the machine.
There are several paths to mess with, but the easiest one is to simply run a .bat file in the startup folder of all users. the batch would look like this.
REM Only mapping a drive
net use z: \\server\share /persistant:yes
REM you can add /user:username password if you need to map it under anothers credentials.
We use a Perl script and a custom module to manage it all for us, but it's all the same process. Ours are done each time you logon. reason for that is mobility. it your mobile, you don't want to waste the machines cpu cycles trying to reconnect to a network resouce that isn't available.
the other thing, is you can specify a login script to run from within AD. This allows it to be managed centrally, and makes it very easy