When you create accounts thier IPs go in thier account setups as normal when you add users. If you have the MysqlCC set up you can go into the accounts tab and fill them out there. The IP in the acconut information should match the users LAN IP (such as 192.168.1.50, 192.168.1.51, 192.168.1.52, and so on)
Walkthrough using MysqlCC:
Click on the EQ data base and click on 'tables' to expand it.
In tables here will be a sub-table called accounts.
Right click and add record.
Fill out the 'Name' column with the accounts name.
Fill out the 'Password' column with the accounts password.
Fill out the 'Status' column with 250 for GM access or lower for player access (I think 20 is for normal players).
Fill out the 'minilogin_id' column with the accounts LAN IP.
Then they should be able to log in and play from thier machine.
I hope this clarifies things for you.
You can find your LAN IP in windows by opening a command prompt and typing
ipconfig. You LAN IP will be the second number called something like:
IP Address. . . . . . . . . . . . .192.168.
'x'.'x'