Map a network drive using a different username/password

net use drive letter \\computer_name\shared folder name or root folder /user:domain name or computer name password

Example:

net use * \\SERVER\Share /USER:darconio password /PERSISTENT:Yes

Using the star (*) will use the first available letter and with PERSISTENT:Yes the drive will be kept even after a reboot

To remove a mapped drive:

net use X: /del

Where X is the letter of the unwanted drive