Depending on which version of DOS/NT you're using:
net use
driveletter \\
servername\
resource /p:
y /user:
DOMAIN\userid
where:
driverletter can be:
Any available drive letter, followed by colon. (e

* - Assigns the next available drive letter.
Any port, followed by colon. (lpt1
servername can be either the shortname of the computer to connect to, or the IP address, or the domain name (for W2K DFS mount points).
resource is the name of the share point or DFS mount point.
/p = Persistent. Either Y or N: Tells the OS whether or not to reconnect the drive the next time the user logs in.
/user = Connect to the server with an ID different from the current user. (Useful when you're configuring a new workstation, so you're logged in as Administrator, but need to connect to a server, to get to the install code.) This will prompt for a password, but will hit against "Bad Password Count", if your domain counts bad password attempts.
--Woodie
(PS: aren't you glad you asked??)